For the slap shot, alignment of the puck is critical. Unlike the other types of shots (wrist shot, snap shot, backhand), you don't start with the puck on your blade. So you must precisely position the puck beforehand. I find that a good position can be determined by this method. Hold your stick at your side, near your hip. About a skate length behind the heel touches the ice is a good distance from your body. Then position the puck somewhere in the middle of your feet. When you're still a novice at the slap shot, look down at the puck while you shoot. That makes it easier.
Regarding the wrist shot and snap shot, the violent, fast push-pull and snap is critical. If you don't do it fast enough, you won't be able to lift the puck very much.
For all shots, practice shooting both from the side and facing the net.
As you get better, try stickhandling a bit before you shoot, like in a game situation. For a backhand, push the puck forward and pull it back for the shot. You need to pull the puck in pretty close to get off a decent backhand. For snap shots, try a toe drag. Or try loading and shooting many pucks in a row -- to get the feel of a quick release.
Extra stuff to work on:
- one-timers (requires a band or bungee cord)
- forehand and backhand passes (requires a band or bungee cord)
- toe drags (requires a band or bungee cord)
- saucer passes