How to throw a Hip Check
You don't see hip checks in the NHL much now a days. Players and coaches have realized that most of the time a hip check is a low risk-reward play. The risk of either taking yourself out of the play if you miss the opposing player simply isn't worth the reward of the solid hit. More often than not, both players are taken out of the play.
When all the planets do align however, the unsuspecting forward can get rocked by a well executed hip check. When lining up your opponent, be sure to bend your knees, keep your back straight, and most importantly KEEP YOU HEAD UP. Youv'e got to get low enough to so that your hip is lower than your opponent's hip. Be strong on your skates with a wide stance as you will need all the help you can get in terms of balance.
Here's a good look at the Canucks Keith Ballard hip check on Malkin:
The timing on a hip check has to be perfect. It involves two moving bodies heading in different directions where the checker has to time both his path and the path of the puck-carrier and adjust his own movement to get to that point of collision at just the right moment.