I ran across this excerpt of Chick Corea practicing a piece by Bach and I
thought I would share it with you. Notice how even a phenomenal pianist like
Corea still breaks his practice down following the basic principles we
discussed back a few months ago: having a defined objective (a specific piece),
highly focused, incorporates immediate feedback (notice how he immediately
stops himself on making a mistake), and pushes the boundaries of his comfort
zone/

https://www.youtube.com/watch?v=na8W-rIUzQw

In particular, look at how he tackles the parts of the pieces that are
challenging him. He slows it down to the point where he can play it correctly
with no mistakes. Then he breaks the part down until he can figure out how he
needs to play it. He even makes notes to himself in the music.