According to Ben Croft, the most important shot in racquetball is the serve. He also talks about changing his pattern of serving straight-in drive and lob serves by mixing in Z-drive and high Z-lob serves.
John Ellis gives a demonstration on how to hit a backhand lob Z serve as perfected by Rocky Carson.
Ben Croft describes how to hit a powerful 1-1/2 step drive serve. Notice how he drives his front leg straight down the court. He stays down throughout the hitting zone and hits the ball about 8-10″ off the floor. His target on the front wall changes according to his position in the service box.
The serve is the most important aspect of racquetball. You have complete control of the speed, angle, height and direction of your serve. Your goal is to either ace the serve or force a weak return of serve.