So maybe you’ve heard of this tactical RPG set in Ukraine, whose main characters are American, voiced in Japanese, developed in China, published in Taiwan, and making money in Korea, a game where guns are represented by cute girls. It must’ve piqued your interest, and next thing you know, you’re reading this guide to “research” this game -- or you’ve already started playing, and you’re not quite sure what you should be focusing on. Well, let us be the first to welcome you to Girls’ Frontline, and we hope you enjoy your stay!
You’re probably thinking that now is the time for the long and arduous re-rolling process so that you start the game with high rarity characters, but actually, there’s no need for that (unless you already know that there’s a character you can’t live without). With all the starting bonuses and gun gacha system, in Girls’ Frontline you can skip the reset marathon. This is because the main draw of the game -- the gun girls (Tactical Dolls, or T-Dolls for short) -- are crafted through farmable, free resources.
In total, there are three types of gachas in this game: T-Dolls, Equipment, and Furniture (which includes costumes for T-Dolls). The T-Doll and Equipment gachas both use free resources, while the Furniture gacha costs gems (the premium currency) but is explicitly for aesthetics. Because of this, it is not necessary to spend real money to succeed at Girls’ Frontline. In fact, the only thing you are guaranteed when you spend enough money are costumes that have no impact on gameplay.
After loading up the app, you might be overwhelmed with all the new terms, UI, and cute girls (of course). Unfortunately, Girls’ Frontline doesn’t do a particularly good job of explaining itself to new players, but fortunately, this guide will walk you through everything you need to know step-by-step.
Before you begin, we have a few tips for you to keep in mind:
- It’s best to concentrate on a single team in the beginning: most of the time you’ll only need one competent team to clear stages due to the friend support system. Since you’ll want to unlock all the game functions as soon as possible, it’s best not to focus too hard on creating more than one effective squad.
- Try to use low rarity dolls at first. Though you may be tempted to use that shiny new maximum rarity T-Doll you obtained, often she won’t be significantly better than your lower rarity T-Dolls at low-to-mid-levels. In general, it’s best not to worry about rarity too much -- even experienced players can sometimes be seen using 2 -- 3 star T-Dolls. Adhering to this rule will help you save certain consumable items called Cores, but we’ll discuss those in-depth later in this guide.
- Don’t forget to Enhance your dolls. Unlike most games, leveling up your T-Dolls won’t improve their stats. What is Enhancement, then? Why do you need to do it? To learn more about it, keep reading.
T-Dolls are classified into different types, each with a general role on the team, which is called an Echelon.
- Handguns (HGs) act as buffers/dodge tanks but they don't do much damage to foes. They buff all types of T-Dolls, making them a good fit for any team composition.
- Assault Rifles (ARs) are balanced. Their high DPS (damage per second) capabilities makes them good back-line fighters. Generally, they buff SMGs.
- Machine Guns (MGs) deal a vast amount of burst damage, but their long reload times and high ammo consumption makes them unsuitable for beginners. Generally, they buff Shotguns (SGs).
- Shotguns (SGs) have low evasion but incredibly high amounts of HP. They also have Armor by default, which makes them great tanks. Their high ration cost and exclusivity to Heavy Production means you won’t be using them starting out. Generally, they buff MGs.
Rifles (RFs) deal high damage and target the back of the enemy’s Echelon, where stronger foes are usually located. Their Rate of Fire (ROF) is low. Generally, they buff HGs.
Submachine Guns (SMGs) are tanks on top of dealing good damage to the enemy’s front lines. They can either have high Evasion (EVA), allowing them to dodge most incoming attacks, or higher HP and lower EVA, meaning that they’ll be absorbing much more damage. Generally, they buff ARs.
HGs are a type of T-Doll that buff their allies regardless of their class.
Resources are the main currency of this game. There are four kinds: Manpower, Ammunition, Rations, and Parts. Many game functions consume these Resources, most notably Crafting and Combat missions. Although Resources can be purchased with premium currency, this is inadvisable as they are easily farmable through Quests and Logistics missions.
You can see your current Resource count at the top of your Home Base screen.
As the star mechanic of this gacha game, crafting is your primary method of obtaining T-Dolls and Equipment. The system is similar to Kantai Collection (Kancolle) in which you spend the four different Resources in varying quantities to produce T-Dolls. These are referred to as Recipes in game and can even be saved for future reference.
Before you start, it’s important to note that crafting T-Dolls requires a consumable item called T-Doll Contracts. These can be farmed through Logistic missions, quests, and are also commonly given as event bonuses.
T-Doll Contracts can be farmed through Logistics missions.
As a beginner, it’s advisable to craft several ARs and SMGs, which can be made using either the in-game recipes, or 30/400/400/91 (30 Manpower, 400 Ammunition, 400 Rations, 91 Parts) and 400/400/30/91 (400 Manpower, 400 Ammunition, 30 Rations, 91 Parts) respectively. Load up your recipe of choice into the easy-bake IOP Production Facilities, and… like some other gacha games, there’s a mandatory wait to get your girl. The production timer, however, not only tells you how long you need to wait, but also which T-Doll you’ve possible rolled. If you’re really itching that gacha action, Quick Production Contracts will make a production instant. These are also easily obtainable through Logistics missions, quests, and events. For more information on T-Doll production, you can find our guide here.
The production screen allows you to choose how many Resources you want to commit to that particular crafting session.
Equipment Production also requires the use of Resources, but uses Equipment Contracts instead of T-Doll Contracts. The ability to craft Equipment is unlocked after completing the 6th mission in chapter 2 of the story missions (2-6). Equipment will boost the stats of your T-Doll, and Equipment Contracts can be farmed in the same manner as T-Doll Contracts.
Aside from what we’ve covered so far, Resources are also consumed in Combat Missions to resupply T-Dolls since they cannot fight without them, Repairing T-Dolls, Equipment Enhancement, and Calibration as well. Farming and conserving resources is key to being able to play the game for extended periods of time and creating lots of T-Dolls, so it’s a good rule of thumb to do your best to carefully manage them.
After completing 30 missions, you will also get access to Heavy Production. The main purpose of Heavy Production is to craft Shotguns (SG). Be aware that this crafting system is a massive drain on resources and should absolutely not be used frequently, as aspiring commanders will quickly find themselves low on all of their resources, their contracts, and cores.
After completing 60 missions, you will also get access to Equipment Heavy Production, which is mainly used to craft Fairies. Like the above it too is a massive drain.
You can read more about Fairies here. Keep in mind, they are a massive drain on your resources and you Combat Data to level properly, so do not feel a need to rush into getting them.
Now that you know what a T-Doll is and how you get them, you may be wondering what all those numbers on their status screen mean. Like most characters in tactical RPGs, T-Dolls each have individual stats that determine how well (or how badly) they perform in combat. The six main stats are the following:
- HP: The amount of health the T-Doll currently possesses. HP is raised when levelling up automatically, but significantly increased by Dummy Linking. The higher a units’ HP, the more incoming attacks they are able to tank.
- Damage (DMG): The amount of damage the T-Doll will deal with each shot to foes. The higher a units’ Damage, the more their individual attacks will reduce a foes’ HP.
- Accuracy (ACC): Determines how accurately the T-Doll is able to target foes with their own attacks. The higher a units’ Accuracy, the less they will miss the opponent when they fire at them.
- Evasion (EVA): Represents how well the T-Doll is able to dodge incoming attacks. The higher a units’ Evasion, the less damage they will take as more attacks from foes will miss them.
- Rate of Fire (ROF): Describes how quickly a T-Doll can fire at the enemy before they can fire again. The higher a units’ Rate of Fire, the more quickly they can shoot at a foe.
- Rounds: Shows how many shots a T-Doll can fire before having to reload (MG and SG only, viewed by hitting Show Equip on formation screen.)
- Armor: Displays how much of a Damage reduction will be applied to incoming attacks. Note that an attack will always do at least 1 Damage unless it is dodged.
- Mobility: A measure of how quickly the T-Doll moves when manually repositioned within a formation in battle. The higher a unit’s Mobility, the easier it is to kite foes with them.
T-Dolls also possess sub-stats as well.These stats are less traditional than the above stats but can also have a significant effect on a T-Doll’s battle prowess, and are as follows:
- Affection: Tracks your bond with a specific T-Doll. Affection starts at base 50, and once it reaches the cap, the ability to perform an Oath with your T-Doll becomes unlocked.
- Oaths are performed with a special item called an Oath Certificate and raise the unit’s affection to 150.
- Affection can only be gained after a T-Doll reaches lv 40, and is raised by giving a T-doll a gift in the Dorms or when a T-Doll participates in a battle.
- A T-Doll whose Affection reaches 90 will have their DMG, ACC, and EVA increased by 5%. There is an additional 5% increase when a T-Doll reaches 140 Affection.
- Current Formation: Informs you of how many times the T-Doll has been Dummy Linked. For more information on Dummy Linking, keep reading.
- Ammo: This tells you how many units of Ammo your T-Doll currently possesses.
- Rations: This tells you how many units of Rations your T-Doll currently possesses.
- Combat Effectiveness: A basic overall measurement of how powerful this particular T-Doll is in battle.
An example of a T-Doll stat screen.
Stats are an important part of a T-Doll’s overall composition. The six main stats will primarily inform you about the role each T-Doll should fill, while her sub-stats will serve to refresh you on what you were doing with her the last time you used her. You can check any of these values by tapping on the yellow magnifying glass once a T-Doll is occupying an Echelon slot, or by holding down on the picture of a T-Doll in the T-Doll selection menu.
In addition to your T-Dolls stats, each T-Doll possesses a semi or fully-unique Skill. These skills can do a wide variety of things, from buffing them self, their team, everyone but themselves, debuffing the enemy, launching grenades, and much, much more.
By going into the Index and selecting a T-Doll, you can check their Skill, see what it does, and get an idea of how it scales by viewing its function at Lv. 10 and Lv. 1.
Aspiring Commanders should be aware that you all skills will start at Lv. 1 and to level them up you have utilize Combat Data by going to the Research section from the main menu. Combat Data can be acquired through Data Mode Combat Simulations, Kalina’s daily gifts, certain events, and rarely, from random nodes. There are 3 kinds of Combat Data; Basic, Intermediate, and Advanced. To fully level a T-Doll’s Skill, you’ll need 600 Basic Data, 1020 Intermediate Data, and 500 Advanced Data.
Unlike some Gachas, the costs for increasing Skill levels are consistent across all rarities.
Like crafting your T-Dolls, leveling their Skills have increasing wait times, capping at 24 hours for Lv. 10. You can skip the wait time by utilizing a Quick Training Contract, however these are nowhere near as common Quick Repairs or even T-Doll Contracts so it is recommended that you save them for especially long wait times.
Leveling your T-Doll’s Skills is extremely important, doing so can increase the amount a stat is increased by the Skill, the duration of the Skill, and reduce the cooldown of the Skill.
When starting out, generally you should prioritize AR DPS Skills (RoF Up, Damage Up), then SMG DPS Skills (Molotovs, HE Grenades, Damage Up), then finally defensive SMG Skills (Smoke Grenades, Stuns, etc.).
In Girls’ Frontline, stats aren’t the only thing that make your T-Doll more or less powerful. There is also a mechanic that determines a T-Dolls overall performance called Dummy Linking, which can be done in the Factory menu.
Dummy Linking is going to be your primary way of significantly increasing your T-Dolls Combat Effectiveness, and basically involves obtaining more copies of a certain T-Doll and merging them into one of her to make her stronger. There are two ways to Dummy link:
- Link by having a literal additional copy of a T-Doll.
- Link by using Cores, which are a wildcard resource that allows you to link any doll. Higher rarity dolls will take more cores -- the amount of Cores needed at each level of Dummy Link is shown in the chart below.
- Cores may be obtained through daily and weekly missions, events, and retiring 3/4/5 star T-Dolls. Additionally, random nodes have a very slight chance of awarding them.
|Lvl 10||Lvl 30||Lvl 70||Lvl 90|
|2 Star||1 Core||1 Core||2 Cores||3 Cores|
|3 Star||3 Cores||3 Cores||6 Cores||9 Cores|
|4 Star||9 Cores||9 Cores||18 Cores||27 Cores|
|5 Star||15 Cores||15 Cores||30 Cores||45 Cores|
If you possess additional copies of a T-Doll, it may cost you no Cores at all to Dummy Link her.
It won’t be possible for you to link your T-Doll right away, and you certainly won’t be able to link her to the maxmimum link level (x5) for a fair while. Dummy linking is first unlocked for a T-Doll when they reach level 10. Additional Dummy Linking (each granting your T-Doll one more clone of herself that she brings into battle) can be performed at level 30, 70, and 90.
So we’ve answered the who, the what, the where, and the when, but how about why? Well, the reason you’d want to Dummy Link a T-Doll is because it essentially doubles, triples, quadruples, and quintuples the original effectiveness of the unit you link in combat. Because of this, it’s best to do it when you can -- assuming you want to use the T-Doll you’re linking for Combat Missions.
The sole reason you wouldn’t want to Dummy Link one of your girls is because it also causes a T-Doll to consume more Resources when deployed in battle. If you’re only using an Echelon to farm low rarity T-Dolls for Enhancement (see below), then Dummy Linking would not only be unnecessary, but also a drain on your Resources.
As one of the other options in the Factory, Enhancement is something that you’re going to be doing often -- this is because it is this function that actually causes your T-Doll to gain stats. So if you neglect Enhancing her, she’ll quickly fall behind.
When T-Doll’s level up, only their stat cap -- as in their stats’ potential maximum value -- is increased. Aside from their HP (which will not see significant gains anyways without Dummy Linking), none of her other stats will actually grow, so a T-Doll will not see a significant improvement in Combat Effectiveness unless she is Enhanced.
Enhancement consumes other T-Dolls as fuel, and each type of T-Doll typically increases a certain stat:
- SMGs mostly give ROF/EVA
- HGs mostly give EVA/ACC
- RFs mostly gives ACC/DMG
- MGs mostly give DMG/ROF
- ARs mostly give DMG/ROF with a bit of EVA/ACC
- SGs give a minuscule amount of DMG/ACC/ROF/EVA
Enhancement can also be performed through a consumable item called Capsules, which will usually increase all stats that have not reached their cap incrementally by 1.
So which T-Dolls should you use to Enhance another? 2 star T-Dolls make for the best Enhancement fodder, as they will not give Cores for Dummy Linking when Retired / Disassembled. This means that if you aren’t using a 2 stat T-Doll in your current Echelon and aren’t planning on using her in the future, you can safely use her to Enhance another T-Doll without worrying -- just be aware that once she’s used as Fodder, you’ll either have to pay a core to get her back through the Index Recall feature or wait to acquire her again. In fact, since there’s a limit of how many T-Dolls you can possess at one time, Enhancement is a valuable tool to help you thin your ranks.
You can see how much a certain stat has been enhanced by looking if there is a golden section on the green stat bar. The more a stat has been enhanced during the session, the bigger the golden section will be.
For more information about Enhancement, our Enhancement guide can be found here.
So now you’ve produced some T-Dolls, and maybe you’re running out of space, or perhaps you’ve just rolled a T-Doll that you find so offensively ineffective that you just want her gone, or maybe you have another T-Doll that fills the same role but does her job better (or has greater waifu potential). What now? Well, you can make your way to the Retirement/Disassembly part of the Factory, and watch your T-Dolls tremble in fear.
Note: For a T-Doll to appear in the retirement screen, she first has to be unlocked through the Armory.
Retire 3 star and above T-Dolls to get Cores, but be warned -- once they’re gone, you’ll have to roll them again through the gacha or make use of the Recovery feature in the Index.
Retirement/Disassembly is the only way to decommission T-Dolls aside from Enhancement, and will be your primary way of obtaining Cores for Dummy Linking outside of quests. This is because Retiring a 3 star or above T-Doll will grant you some Cores, which means that technically they are a farmable item as well. Because (like Enhancement) a T-Doll that is Retired cannot be retrieved unless you obtain her again from production, as a drop, or make use of the Recovery feature, it’s advisable that you only Retire T-Dolls that you’re certain you aren’t going to use. Below is a chart that shows how many Cores are granted for Retiring certain rarities of T-Dolls:
|T-Doll Rarity||Cores granted when Retired|
Well, you didn’t just expect your T-Dolls to constantly be on the battlefield, did you? The Dorms are where your T-Dolls relax and hang out when they’re not fighting -- and besides giving you a chance to look at their adorable chibi sprites, the Dorms are also where you can obtain Batteries, give Gifts to your T-Dolls, and create and gift Combat Reports.
Batteries are another type of consumable item that essentially function as currency. They are exchanged for Progress Reports, are used to upgrade the facilities in the Data Room, and adopt pets. They can be obtained from your Dorm at 3:00 to 6:00 [UTC] and 19:00 to 23:00 [UTC] and can be obtained from your Friend’s Dorms at 11:00 [UTC] and 23:00 [UTC], replenishing every 12 hours.
Batteries in your dorm are collected from this black device -- the Battery Condenser -- during certain times. When it isn’t the right time, the condenser won’t appear in your dorm.
The amount of Batteries granted from a Friend’s Dorm depends on how many Dorms that friend possesses. The minimum Battery grant is 2, and the maximum is 10. Do note that there are a limited amount of Batteries that a single friend can grant each reset. If you know one of your friends has more Dorms than the others, prioritize collecting Batteries from them asap!
You can also purchase more Dorms with Gems, which will increase your condensers battery capacity by 80 each, and obviously allow for more comfort and battery generation. This makes acquiring more dorms a great help for upgrading the Data Room, Rescue Station, and Fairy Chamber quicker.
Combat Reports draw from a pool of Surplus EXP that is granted to you after every battle you complete. Combat Reports allow you to grant this Surplus EXP to your T-Dolls, enabling them to level up without battling. Pets raise the Comfort of your Dorm, and level up the facilities in the Data Room, Rescue Station, and Fairy Chamber.
Combat Reports are created in the Data Room, which can be found under the Auxiliary Rooms menu.
Gifts are special items that you can give to your T-Dolls in order to raise their Affection. Once you’ve gotten a gift, it can be found in the Gifts tab of the Warehouse, where it can be then selected to give to any one of your T-Dolls who are currently in your dorm. Do note that your T-Dolls will appear in the numbered dorm corresponding to the number of their Echelon -- Echelon 1 appears in the No.1 Dorm, Echelon 2 appears in the No.2 Dorm, etc. If you want to give a T-Doll a gift and she’s not appearing, try moving her into your first Echelon and see if she shows up.
Gifts and Combat Reports can be found under the Gift tab of the Warehouse menu. Here, you can choose to give them to a T-Doll.
Finally, Comfort is a value that is increased with Furniture and Pets. The higher it is, the more additional Batteries it grants you when you collect them from your Dorm. Furniture can be obtained from the Re-Supply menu, and consume a currency called Tokens. You can also obtain special T-Doll costumes from this gacha, but be warned -- there is no confirmation menu, so only click the purchase button if you’re prepared to spend your tokens.
The Battle System
The goal in a GFL battle is to capture the enemy’s base, and plays much like a tactical RPG crossed with Risk. Your team/Echelon will start the map by being deployed to a Command Center. The enemy’s team will occupy various Nodes on the map. Nodes are captured by landing on a Node and staying on it until the next turn.
Become victorious by capturing the Enemy’s base.
If all your Echelons fall in battle or your Command Center is captured by a foe, it’s game over!
There are penalties to only partial defeat, however -- if any of your T-Dolls reach 0 HP, it causes all T-Dolls in the Echelon to lose Affection.
Entering a battle with no Rations or Ammo will result in a loss of the battle and your Echelon withdrawing. Withdrawing an Echelon from battle will result in loss of all Rations and Ammo they had on their person when they withdrew. Echelons consume a certain amount of Rations every turn (even when they’re not fighting) and 1/5th of their Ammo each time their enter a skirmish. You can resupply your Rations and Ammo at a Command Center or Heliport.
Finally, Terminating a mission will result in all Echelons on the map losing their Rations and Ammo, but will not result in lost Affection. If the battle is going south, don’t hesitate to Terminate the mission and return when your Echelon has become a bit stronger.
Don’t be afraid to Terminate a mission if it’s not going well for you -- the only thing you’ll lose is the Ammo and Rations that your Echelons are currently holding. If you don’t even need to do any major repairs, you can just hit restart and try again. Be warned that there’s no confirmation, so as soon as you hit the button the mission will restart/terminate.
Deployment is the first thing you do on a map, and is how you choose which of your Echelons will be initially participating in the fight. In order to deploy, you need to tap your Command Center (the Command Center colored blue) and choose your Echelon to deploy it and start the map.
If an Echelon is Logistics, is Autobattling, or one of its members is somehow occupied -- like if she’s being Repaired or undergoing Skill Training -- you won’t be able to deploy that specific Echelon.
Retiring Echelons standing on a Heliport or Command Center allows them to keep their supplies, however, it will still count as a retreat and disqualify you from S-ranking the map on that run.
Nodes labelled Heliports that have been captured by you or your allies (that are colored blue) can also be used to deploy an Echelon or a Support Echelon. Additional Echelons and Support Echelons can also be deployed from the Command Center, assuming it is not currently occupied by an Echelon.
Additional Echelons of yours can be deployed on captured but unoccupied Heliports or your unoccupied Command Center.
Support Echelons are essentially Echelons that don’t belong to you that you can still use in battle, and can be deployed onto an unoccupied Command Center or Heliport for no cost of Action Points. They can be used a total of 20 times daily, though once a Support Echelon is used, that specific team will gain a cooldown timer and will be unavailable until the timer runs out. The currently equipped Support Echelon can be found at the bottom of a Friend ID card.
Note: Griffin’s Support Echelon does not have a cooldown timer, and Support Echelon takedowns do not count towards the S-rank kill count in general.
Support Echelons can be deployed just like another one of your Echelons. Double tap them to issue commands.
Although you can only issue them basic commands instead of controlling them directly, Support Echelons still can prove to be amazingly useful allies in battle.
- The Standby command causes a Support Echelon to simply wait on the Command Center or Heliport they were deployed to. They will battle any Enemy that lands on the Node they’re on, but they will not leave where they’re stationed, even if it is in danger of being Encircled. Friend Support Echelons who are deployed automatically have this command active.
- The Eliminate Enemies command causes a Support Echelon to chase after the foes closest to them, indiscriminately of the current status of Heliports or Command Centers. Grifon Support Echelons who are deployed automatically have this command active.
- The Capture HQ command causes a Support Echelon to make a beeline for the enemy’s Command Center. This is a good command to choose if your deployed Echelon is a bit weaker than your foes and you want to complete the map as soon as possible.
You can issue any Support Echelon a new command by tapping on it twice.
During your average battle in Girls’ Frontline, you’ll encounter many different kinds of Nodes. Each of them have different functions, so try to make use of them whenever you can.
- Command Center: The main base of a faction. You deploy one Echelon at your Command Center to start the battle, and an Action Point can be spent on your turn to deploy another one of your own Echelons here -- provided the Command Center isn’t currently occupied. You win Standard (and Emergency) battles by capturing the enemy’s Command Center.
- Heliport Node: Similarly to the Command Center, you can deploy Echelons at allied Heliports. Each Heliport captured also grants you one more Action Point on your turn.
- Random Node: Each Random Node is marked by a “?” symbol and has a random effect when you wait on it. Usually these Nodes add to or subtract from your Resource count, but be aware that you can be ambushed by enemy Echelons.
- Blank Node: Provides no particular effects or benefits, however it is still recommended to capture them to avoid Encirclement.
- Radar Node: A special Node that only appears in Night maps. Capturing a Radar node grants vision in a 2-Node radius around it (the first two nodes extending in any direction or combination of directions from the Radar node).
- Supply Point Node: A special node that so far only appears in events and 9-Emergency. These nodes can be used to resupply once before turning into a normal node. It does not have to be captured to be used.
- Time Limited Heliport: A special node that so far only appears in events and 9-Emergency. These nodes are heliports that can only be resupplied/deployed on when their turn timer ends.
- Inactive Heliport: A special node that is functionally a permanently closed Time Limited Heliport.
If you capture every Node that surrounds another Node, that node will be Encircled and captured at the start of your next turn. This is a good way to avoid battling powerful units that remain stationary on Command Center nodes.
Encircled Nodes will display a notification of their imminent capture, so it’s important to pay attention to the flow of battle.
Do note, however, that your foes can and will use Encirclement tactics to their advantage. Be wary of enemies approaching your Heliports and/or Command Center, and also be aware of moving isolated Echelons to capture nodes in enemy territory, as the enemy may simply move around you and recapture their nodes via Encirclement. Encircled Heliports will not resupply your Echelon, cannot deploy additional allied Echelons, and may deploy additional enemies, so you will need to carefully capture them if you want them to be any use to you.
There are 3 different types of Medals awarded for completing a map: Bronze, Silver, and Gold.
- Bronze Medals are awarded for completing the map.
- Silver Medals are awarded for capturing every Node on the map.
- Gold Medals are typically awarded for obtaining an S Rank and therefore meeting certain requirements.
To discern what conditions you will need to fulfill to earn a Gold Medal, check the Combat tab at the top of the Battle UI. An S rank will be awarded if the Gold medal condition is met.
At the bottom of the UI once a battle is entered, you will see various icons that all have cooldown timers. These are your T-Doll’s Skills, and using them effectively will help you prevail in battle.
The bottom of the battle UI is where your T-Doll’s skills are located. Once it is no longer greyed out, you can tap on a skill to activate it. Alternatively, you can use the Auto Skill function to instantly activate skills once their timer is up.
There’s many different types of skills -- some debuff foes, some buff the T-Doll herself or her allies, some fire special missiles that do more damage than regular bullets, and some do something completely different. If you want to learn more about your T-Doll’s skill, you can check it on the same status screen where you can check her stats.
Skills can be leveled up through Skill Training, scroll back up to Skills for more information regarding this.
You can also Move your T-Dolls into different positions once a battle has begun -- and this will not affect your formations buffs. If one of your T-Dolls is heavily damaged, swap her with an ally who has a similar function (a tank with a tank, etc) so that they can split the burden.