I always do something like this when I'm learning a new character:
A) Check out the movelist and more or less decide on which moves you want to use often and rarely. With Alisa I can divide those moves into about 3 categories. This is all personal preference, but it gives you a rough idea. I usually use a frame data list to go through the moves, so I can read the frames at the same time.
1) My main moves: 1, b+1, d/b+3, d/f+4, d/f+1, ws+4,
2) Moves I use relatively often: d/f+2, 1,2, iWR+2, grabs, f+2, FC d/f+1+2, 1,1, ws+1+2, d/b+4, b+2,4, d/f+1,4
3) Situational moves: 2,3,3, 4, u/f+4,4, b+3+4, u/f+3,2, boot and chainsaws, d/b+1,1, iWR+3,4
B) Learn juggles. Just check the combo thread and learn one juggle of each launcher. Generally the staple is b+1, ws+1,2, f+1, b+4,3 B! if the launcher doesn't bind, and something like f+2, 1,1, d+3,1+2 if the launcher binds. Also learn some wall carry variations and wall combos.
C) Find out how you're actually going to play Alisa. The two simplest ways of doing that is watching vids of top players and just playing matches yourself. If Chanel or whoever is doing good in Tekken Crash with Alisa, chances are he knows how to play the character, and chances are you can learn a few things watching those vids. Also learn all oki, wall game etc. You can read about that here in TZ and watch vids/try out stuff yourself.
D) That's it, you know how to play Alisa. But I'm guessing you don't know how to play Tekken. There's one thing you need to perfect if you want to win with Alisa, and that's movement. And with Alisa it's absolutely necessary to play her. If you don't want to spend hours learning backdash canceling, you shouldn't play Alisa. Practice throw breaking too.
Seems we got a lot a new player. Well I will set you straight. lilleboff I am glad this guy became a moderator. He by far will give you the most solid advice. Are you a beginner / newb in Tekken Period? Or with Just alisa. narrowing down how bad or how good you are will help speed up what I need to tell you. To help you improve.