This is one of the best ball machine drills for learning and practicing stroke variety: placement and spin control.
The ball machine will feed balls deep to my forehand side.
I will practice series of 3 balls: 1 topspin forehand deep, 1 slice forehand deep, and 1 drop-shot; each shot will go in a different direction than the previous one, alternating between cross-court and down-the-line.
Technical aspects to be considered:

- for the topspin forehand groundstroke, keep the wrist relaxed, use a semi-western grip, and impart lots of spin by brushing up on the back of the ball; the harder you swing, the more spin you need.
- for the slice groundstroke, use a continental grip and begin with the racquet head higher than the eventual point of contact in order to swing down and forward to create the underspin effect on the ball; the result is a ball that bounces low.
- when hitting drop-shots use a continental grip, short backswing, and prepare the racquet head higher than the eventual point of contact to be able to swing down on the ball for underspin effect; open the racquet face at contact for extra spin.

Secrets:
- Topspin Forehand Groundstroke: Hold on to the racquet neck with your non-dominant hand to limit the backswing and coil the upper body which will translate in more power when swinging at the ball.
- Slice Forehand Groundstroke: Prepare with the racquet head higher than the shoulder so you can swing down at the ball for slice and power.
- Forehand Drop-Shot: Cushion the ball at impact while opening the racquet face for an extra spin (like catching an egg on a pillow).