Kenny Werner describes the process:
‘I never try to play anything I’m practicing. I’m only interested in the effect practicing has on my playing.”
Practice as slowly as necessary in order to play the most difficult passages cleanly and in rhythm.
Most players make the mistake of trying to play things too quickly. This reinforces bad technique and poor rhythm.
Start slowly and gradually increase the tempo.
An alternative to this slow, gradual approach is to practice at fast tempos but only a small portion of the exercise, gradually adding more notes until the entire passage is learned.
Extend the range, change the rhythm or create your own variations of each exercise.
Experiment with a variety of rhythmic accents and expressive devices.
Do not try to practice too many concepts simultaneously. It is better to thoroughly master a few patterns that appeal to you, rather than to superficially practice a large amount of material.
Whatever you choose to practice, work on it until you can play it without having to think about it. Only when you have learned something at this deep level will you be able to merge in an unpremeditated manner during an improvisation.
Sing while fingering the instrument without playing.
Also try practising away from the piano while imagining yourself playing.