1. PLAY JUST CLEAR OF THE SHARPS
Play natural keys just clear of the sharps, and avoid playing up in the gaps--that is, between B and C and between E and F. It is more difficult to move the foot from side to side when you are “caught” in the gaps.
Also avoid playing back on the naturals towards the bench. The angles of the legs and feet are optimized when playing further forward, offering greater control and relaxation. In addition, it takes more motion to move from the natural to the sharp if your feet have to travel from underneath the bench.
Remember that economy of motion is particularly important when the motion is repeated frequently, such as moving back and forth from natural to sharp.