There’s a reason why Final Sky is also called Cross Summoner – you can summon all those characters and have them serve you. But over time, some of those characters may outlive their usefulness, and you’ll need to make room for newer, more powerful characters. The only way to dispose your unwanted characters is to sell them for more coins. You can then use those coins to level up your cards away from the battlefield; free experience, on the other hand, is earned while taking part in battle.
Even if you might end up with a superfluous character at some point, that shouldn’t stop you from summoning whenever you could. Your leader should have ridiculous powers, which would then allow other players to choose him/her; if that happens, you get summoning points. Use your summon stones to get some rare characters, which will invariably be more powerful and more effective in battle.
You don’t want to resort to button-mashing when executing combos in Final Sky. That’s going to reduce the efficacy of your overall attack, and prevent you from successfully pulling off a combo. Your special attacks must be used to send your enemy into the air, and since combos break following an ace attack, you’ll want to finish off the enemy with that ace attack. More combos, aside from meaning more damage, also mean more blue orbs for you.
Your character will get a Limit Break when you get that character twice, and that too applies when you use the correct Limit Materia. It’s important to use the specific Limit Materia to increase star rating and improve rarity.
This isn’t exactly your usual encouragement to compete in multiplayer action – there are some real benefits to playing other modes aside from single-player. Final Sky has dailies in the form of dungeons, and these can earn you some rare rewards if you complete them. You can also head to the arena for PvP battle, and as you increase in rank, you’ll earn better league rewards.