Some kihon (basics) striking drill for practice outside of class.
Solo training, without a training partner.
Start with the 18 fists, and practice striking in the air, using footwork in time with the hand used for the strike- or head, elbow, etc.
The idea is that the martial arts *fist* is connected to the same timing of the legs- as the legs move the arms move. As the legs stop moving, the arms stop moving.
Naturally, also paying attention to correct spinal and hip alignment, relaxed movement (nagare), etc.
Drill the movements hundreds of times.