1. Practice chords and arpeggios- these will give you the fingering memory that you can call upon when needed.
2. Practice them SLOWLY, SLOWLY, slowly getting faster, like Count von Count's song. When you're playing it too fast for your own body, it sounds sloppy, and it really doesn't feel "smooth" under your fingers either. So, slow it down, and SLOWLY, SLOWLY, SLOWLY GET IT FASTER.
3. Play the accompaniment SOFTLY- this is not only for the music (i.e. let the melody shine), it is also for your muscles (i.e. facilitate relaxation and improve endurance).
4. Do not use your shoulder to bring up your hand.
5. The lower you sit, the more conscious you must be about having your wrist "up".
6. Have some fun whiplashing your wrist about the keys. (Move your wrist

)