There are these two ways that you can try and see an emphasis on wrist action. Maybe you'll find one works better for you than the other.
1. Keep your wrist firm and the angle between the forearm and the fist relatively fixed, hit the ball all the way into the followthrough with the configuration.
2. Keep your wrist loose like you can knock on a door with just moving your fist. On the forward swing, sort of stop your arm early, like while your elbow and forarm are aligning to your body, and then let your wrist joint move forward from that point.
For me, 2 seems to add more power