This drill works all the different serves in your repertoire: flat, slice, and top-spin serves going down the middle, wide, and to the body of the opponent.
Place 6 cones or markers on the court as shown by the orange circles in the below picture.
1) Start with a basked of balls and serve 3 flat serves aiming for cone 1. Then serve 3 slice serves again aiming for cone 1. Then serve 3 top-spin serves again aiming for cone 1. If a player doesn’t know how to do slice or top-spin serves then just skip that type of serve.
2) Repeat the serve sequence (3 flat, 3 slice, and 3 top-spin serves) but now aim all the serves at cone 2.
3-6) Continue this pattern until you have served at all of the 6 cones.