Pretty much the best way to get better is to practice more. People may be able to show you some moves, but in my opinion the best way to learn is just to keep practicing. A method of getting ideas for replays is to look through the replay board. Usually inspiration will strike when you're watching a replay and think to yourself "I could do that better", or maybe you'll think it looks really cool, so you keep trying to get something similar.
But the best way of making moves and doing well is to practice.