A talented student of mine is currently working on Chopin’s famous Fantasie Impromptu. The obvious challenge here is the cross-rhythm: right hand sixteenth notes against left hand triplets. I have devised the following 10-step guide to help my student nail this:
1. Practice each hand separately, very slowly, make every note extra louder than normal.
2. Practice each hand separately, still very slowly, but instead of making every note extra louder, just accent the first note of each group – first note of the group of four sixteenth notes in right hand and first note of triplet group in left hand.
3. Put hands together, one hand extra louder than the other, still very slowly – you can choose which hand you want to play loud first, although it is often a good idea to play the non-melody hand louder first, as that is often where the problem is.
4. Repeat step 3, but instead of making every note extra louder, just accent the first note of each group.
5. Repeat steps 3 and 4, but make the other hand louder this time.
6. Play “normal” (musically, without the exaggerated accents, and bring out melody), but still under speed.
7. Repeat step 6, gradually increase tempo.
8. By now you should just “feel” the music; DO NOT over-analyze mathematically.
9. Consciously make yourself listen to each hand, as soon as unevenness is heard, repeat steps 1-5.
10. Even when the desired tempo is eventually reached and the cross-rhythm seems right, it is still important to repeat the above steps every now and then, especially the “slow practice” part!
I hope others may find this guide helpful!