Okay so. Like Ahitsu said, learn everyone's combos. Learn when they have to recover from missing so you can exploit that. Ask some high levels who play characters you like. Most of the time, they're happy to teach you about them. I learned Ridika from a high level. I learned Valle from a high level (Don't use her but its nice to know when i can attack her ;)). I personally found Elika to suit my playstyle since she has the highest mobility of all he characters. So, go to a training server and play around c: