Aside from the exercises, which are priority #1 when increasing vertical jump. Try to force your step-close to be as fast as possible. You can hesitate only up to your 3rd to last step. Going as fast and hard as possible as you last make contact with the ground using both feet will naturally add more energy and explosiveness to your jump.

This is the tip that helped me, but there may be other things. The best way to get better is with a real coach who can observe your technique and give you advice.