What you need to work on is your reflexes when using your ability. You've got to get yourself so used to it that it becomes second nature to phase or solidify at a moment's notice, and not necessarily as a response to danger. If you can do that, you won't need to work on your landings, because you'll be able to use your ability with refined enough precision to control how you move through any environment, under any circumstances.

[Teaching Xavier is teaching, trying to make up for being such a fail!teacher since coming here.]