Gotta pick your fights carefully and be patient mostly. Know when to commit and all that. Don't try to shove your face in if you're getting double locked and stuff.
For Epyon specific stuff you'll want the Install done with AC on all the time, so just pop it at round start and Spawn. It increases damage and mobility so there's really no reason to leave it off. When you get a melee hit, use A to cancel instead of stepping so just do like BABABABA (amount of times you can do it varies on starter) into an ender (something like B~BC) for your combos.
If you're fighting melee suits you can use your whip to keep them honest too. 4/6AB and 5AB are good for horizontal and vertical attacks.
If you aren't used to playing melee I'd start with something with more traditional neutral tools like X1 Kai till you get comfortable with the neutral/concept. Epyon is pretty hard to play neutral with and you miss on good habits.
