How can I serve harder?

1. Consistent toss in front of your hitting shoulder.
2. Step into the serve with your opposite foot to transfer body weight.
3. High elbow and a fast, loose arm swing.
4. Contact with a firm hand — heel of the hand for float, snap over the top for topspin.
5. Build shoulder and core strength.

Power is nothing without accuracy: aim for zones before chasing speed.