Learn the basic rhythmic subdivisions and practice accurate timing. Use your whatever finger you like to play clawhammer with-index or middle finger. This simple exercise is a good opportunity to try both if you're unsure of which to use. Strive for control of your dynamics. Be able to play this loudly or quietly and switch from one to the other. Practicing crescendos(slowly getting louder) or decrescendos within sections is also good practice.Learn
More about One Finger Workouts
One finger workouts help you develop rhythm rudiments and technique by focusing on one finger at a time.