Pointless movements look bad, every move you make should be leading to something.
Before you start moving, first have an idea in your head what you are going for, and then aim for it. If you just move and hope for something fun to happen, you are bound to make lots of pointless moves and it makes the replays look bad.
R (replay) and E (edit) are your friends, use them. When you want to pinpoint some close move or max efficiency on a hit, use shift+space to move one frame at time.
I'm new myself too, the more experienced people should be able to be more accurate, but that should help too.