The #1 Kick Serve Killer 

Check out "Spin It!" here: bit.ly/3W2S0Av
The reason so many tennis players struggle to hit a kick serve is because they have a poor side-on position. In other words, they don't stay sideways long enough. They open up too early, which makes it impossible to swing from 7 to 11 and generate the spin that causes the ball to hook through the air and kick up in the opposite direction when it bounces.
In this video, Dr. Mark Kovacs shares a drill from inside "Spin It!" that fixes the poor side-on position mistake. If you like what you see, then click the link above to pick up a copy - inside you'll get 30+ drills that show you how to generate spin from your entire body.