Notice: This is made before CBT even starts, so this is just me assuming what is in the game and what everything does. However most things are the same in almost all browsers so keep that in mind while playing the game.
After having played many browser games and mmorpgs in general, I think its about time I offered a few tricks/guides/tips or w/e you want to call it to give back.
1. Determine your play style. You can overpower your opponents, dodge all their attacks, etc.
2. Main hero
The starting class that you pick will determine what you will become in the future and how you'll build your team. Currently there are 3 classes you can pick from Magic Knight/Gunslinger/Elementalist. Each class has two paths they can go down when deciding your skills (Can reset them at any time *maybe with gold*). The paths are pretty simple each having an offensive and defensive side. You can only pick one side, so its nice to know what you want.
Magic Knight - Melee
Gunslinger - Ranged DPS
Elementalist - Ranged Magic DPS
2. Recruitment
Starting out the game you'll get the basic recruits, just play with them until the tutorial gets done or you find the right time to trade them out. Usually in the early stages of the game you can run straight through everything with no healer, but in later stages you'll need one. If there is a recommended partner tab in this game, I think following that for the first half of the game wouldn't be too bad. Since it will give you something to start out with. Recommended to recruit partners with S rank potential or higher.
3. Formation
There are a total of 7 spots in the formation, which of only 5 can be filled (Main + 4 partners = 5). 1 Front line, 3 mid assaulter, 3 backline dps or support. Formation does help a lot in battles since it determines which of your characters attacks in what order.
4. Gear
Keep all your characters geared, with the most current gear or close to the most current. Gear will likely go in Green>Blue>Purple>Yellow with Yellow being the best and Green gear being the worse. The gear you want to get is the ones you will have to either forge or get shards from. Gear effects your characters differently, therefore when you refine/reforge for stats it is best to keep that in mind. You wouldn't want a tank character with a lot of Int.
Since we are on the topic of gear, you'll also need to keep it reinforced/fortify. Usually the cap for this is your own level. Not only will this increase your BR/BP it will allow you to hit harder/survive longer in fights. Usually most people upgrade Weapon > Shoes first then upgrade whatever else they have. Since weapon increase your damage and shoes will increase your speed, which will determine who strikes first.
Gems will be one of the last things you get to in the tutorial. I'd save up my free gold on this and a few other things. Gems will greatly increase your BR/BP and depending on what gems you socket as well as their grade can help your play style out. The higher grade gems will help more. I'm going to assume this game will give you a % based stats instead of actually saying how much it will increase your stats by. Gems will go 1>2>3>4>5>6>7>8>9>10 (Maybe up to 12). gems at level 10 will give you the best advantage.
5. Events
Starting from day 1 of the game, it usually has a 7 day event which will lead you in a great direction into increasing your strength. In the cash shop they may also have discounts on certain days for certain items so you should pay attention to that as well. However some things in the cash shop are pretty useless so it is best not to worry about them. Just do as many events as you can every day, so you can increase yourself overall.
6. Pets and mounts
Pets will give you a variety of stats, therefore keep them up to date as much as you can. I'd do the same with mounts considering Mounts > Pets most of the time. Meaning Mounts offer more BP/BR than pets do, but both are important.
7. Guild
Join/Make a guild as soon as you can to gain the most benefits. Guilds offer an increase in buffs that will increase your teams stats. The higher the guild, the better stats you can obtain. These come at a cost such as guild donation/contribution points. Which can be obtained by donating silver/gold to the guild. Gold offers a higher amount of contribution points than silver, and silver has a limited amount you can donate daily.
8. Star Chart
This is a basic stat increase where you run dungeons and gather stardust to increase stats. As long as you continue to dungeon this will increase, not that great of a thing, but does help increase BP/BR.
With everything i've stated above, you must wonder what you should focus on.
1. Main/Sub Hero
You will want to mainly focus on your main hero over the rest of your team. This is mostly due to the fact that your main character will always dish out more damage than the rest and their stats are better. Not only that you can pick their skills/passives unlike the Sub heros. Depending on what main you pick will determine what other heros you should focus on in your team. I'd say it is best to have 2/3 that are always powered up and you know will survive the longest. Yet! While I say that, you have to know if they are a good partner to have and if it is worth investing in them.
Sub Hero's like Natsu who have S+ potential are nice to invest in since you know they will stay with you for a while. But there may be surprises of other A rank potential Sub Heros who are better in a certain way.
By investing I mean like, leveling them up to the max then reincarnating them over and over until it can't be done anymore. You'll also increase their star rank to get them to a higher grade. Rank them up to gain better stats/skills. Awaken them (Whatever that does) and you'll obtain their exclusives. All of this takes time/gold/silver/materials. It is not known if you can inherit one Sub hero gear/stats/rank/awakening etc. to another.
2. Pets/Mounts
This is the second thing you will want to focus on, considering that this will increase the overall performance of your whole team and not only yourself. Keep these leveled!