I mean it's kinda just look up forums where people that play the game much longer than you have combos already written down
Another thing you can do is just go on the training mode and try to make your own freestyle combos that you can remember without dropping
And the last option I really have is just see other gameplay and see how you can wrek people that way www.youtube.com/user/margherita0141/featured Is my favorite Skullgirls fighter channel