Tap, Tap, Tap

The feeder is at the net on one side with a basket of balls ready.
The player stands at the service line, in ready position, on the other side.
The feeder will toss each ball by hand so that they land short in the opposite service court; the player will have to sprint and tap the ball over the net before it bounces twice. Then, he will recover quickly and head back to the service line.
Repeat this about 10 to 15 times.
This is a good drill for conditioning, leg strength, racquet and ball control.