Move It!

Move It! is for older players, advanced beginners and up (although of course at the end of this article I will give you some ideas on how to make it easier for beginning players). They should be able to rally and direct the ball. If they can't direct the ball yet, Move It! will help them get there.

Move It! comes in two variations. One is to learn to move your opponent from side to side. The other is to move them deep to short. You will need two different colored spots.

Side to Side

Dust off your spots - you will need them
 for this drill

Place one spot on the ad side of the court, and one on the deuce side. Where is not especially important as long as they can be seen across the net from the far baseline. Two players rally singles. One is challenged to call out which side or color spot they are hitting to as they hit. Both players must recover to center baseline after every shot.

Deep to Short
Same idea, but now one spot is placed in front of service line and the other behind the service line. Player must call out the color of the spot or 'short'/'deep' before each shot and make it happen. This will be a workout for the returning player, as both will still be expected to recover to center baseline after every shot.

Give each players either 10 balls and switch, or switch after a set time limit so that each player has a turn at directing the ball.
Variation
For your young beginners, instead of rallying, have them tossing and catching with foam or red balls on the 36-foot court.

Adapted from USTA's QuickStart Tennis guide