This is my "go to" practice method for almost every piece. I first learned this technique from Eliane Lust. This method moves you through difficult passages beat by beat.
Basically it works this way:
- Start with a difficult passage (leaps, scale runs, tricky turns, etc.)
- With the first note and/or chord of the first beat of the passage held down, think about what comes next in the beat, but don't move your hand or play it yet. Check carefully to make sure that the hand, arm, and fingers are in the exact right position to begin the passage.
- As soon as you have thought out where to move next, play up to the next beat as quickly as possible, but not beyond.
- If you miss notes - do the same transition again.
- Sometimes you may only be able to play up to the half beat in one move, depending on the difficulty of the passage.
- You may also need to do this work hands alone, then repeat the above impulse practice steps "hands together".
Repeat the above transition until one beat is perfect, then move to the next and repeat the above.
The next step is to put multiple beats together (from beat to beat to beat) until you have the entire passage up to tempo and mastered.
As you might have guessed, impulse practice is related to muscle memory practice; after practicing a passage with the impulse method, you most definitely have developed muscle memory for that passage.