Practicing frequently and efficiently creates muscle memory (which technically occurs in the brain) along with confidence and increased skills. These benefits translate into calm, patient pickleball.

No law proclaims that you must drill to play good pickleball. If practice drills don’t bring you joy, don’t do them. Pickleball should be about enhancing your life with joyful play, not tedious drudgery. However, if you do enjoy drilling and the improvement that comes with it, then by all means drill! When drilling, we recommend that you:
 

• Start in a cooperative way. The first ball is a "courtesy feed," meaning that if you’re practicing volleys, don’t start with an untouchable slam at your drilling partner’s feet. You may need to make a rule that the first two or three touches must be gentle dinks.
• Build increasing difficulty. The best drills have progressive phases, so as you master one phase, you can move on to a slightly more difficult version. Vary the speed or height of the ball, shrink the target, or require more movement.
• Add a competitive element. Many players need this element to keep interest and focus. Have some way of keeping score or earning bonus points when players successfully perform the desired skills.
• Practice from both sides. Practice all skills from both the right and left side of the court, using both forehands and backhands.
• Have plenty of balls. Don’t waste your precious drilling time chasing balls if you can avoid it. A hopper, bucket, or pouch full of balls makes practicing easier.
• Be creative! Make up your own drills, and continue to tweak ones you’ve learned to make them as fun and challenging as possible. 

Pickleball For Dummies contains favorite drills for 1-4 people, and for those who hate drilling, suggestions on how to practice while you play.