Scientific studies have been done about the wrist shot, and hockey obsessed people like me have read them. One interesting (and maybe somewhat obvious) point for producing power in your shot is contact time.
Contact time is the amount of time the puck is in contact with your stick blade from the beginning to the end of your shot. Studies show the more time the puck is on your blade during the shot, the more time you have to add more power to your shot. In comes our video on pulling the puck back.
To get more power in your shot, grab about 20 pucks and practice pulling the puck back before you shoot. Pull it back to different spots, sometimes only a few inches, other times well behind your back foot. Work on different body positions as well.