There are 4 main characters I use, and different strategies for each one (2 of them being cheap).

1. Cloud is mostly my farming guy, cause I can kill stuff with him the quickest. He's the one I use on time attack to build up wind/water/life stones and megalixirs. My strategy with him is simple: lure them into a brave attack, block, and counter with either Slashing Blow > Omnislash Version 5 (for the added Wall Break damage), or Sonic Break > Finishing Touch. Strategies vary slightly tho, depending on who I'm fighting (particularly Kuja or Ultimecia). I can also substitute Tidus for Cloud, because he's pretty similar minus the Wall Break.

2. Terra is my cheapo #1. I just jump at the top of the stage, and rain down the Holy/Ultima Combo until they give in. No matter the level, she is basically the anti-Chaos. She really ruins his day (especially using her Tornado to interrupt Divine Judgement from anywhere).

3. Dark Knight Cecil is my cheapo #2. Just spam Dark Flame, which goes through walls and has pretty nice homing, and I can kill anything. Basically I just use him to build chain 100+ in the Blackjack dual colloseum.

4. My favorite to use, and the fun one, is Jecht. For one, I like the character. I like his taunts after he wins ("How good can one guy get?"). He is also *potentially* the most powerful character because of his combos. His combos are very difficult to pull off and master tho, which is why I probably don't use him as much as Cloud.

For all characters, I use one of two builds. For stuff my level and below, its Exp > Ex Force. For stuff thats higher level than me, its Exp > Bravery. You can kill level 150 stuff in Blackjack in 3 HP attacks with the proper Exp > Brave build.

And now I hope I never fight any of you online, because you know my strategies.