Strengthen Gluteus Medius ( and a little about Gluteus Minimus:
Start : Clam shell: http://www.youtube.com/watch?v=ziw6tJTcBGQ
Lie on your right side with your back to a wall. Stack your left leg on top of your right. bend your knees so your feet are at the wall. Your hips should face forward. Bend your right arm, and place it beneath your head for support. Your left arm can lie on your left thigh or rest on the ground in front of your stomach.