Just wanted to share some pretty good exercises/ stretches you can do to help prevent Runner's Knee. These along with drinking plenty of water, wearing good sneaks with sport gel inserts, stretching before and after each run, and icing my knees after a particularly hard run has definitively helped.

Standing Leg Lifts
Stand with your back against the wall. Lift one leg up as high as you can with the knee straight. Hold for five seconds, then bend your knee to relax, hold for five seconds. Straighten your leg again, and do five of these before switching to the other leg. Over time, see if you can build up to ten seconds.

Foot Turns
Lie down or sit in a chair and stretch both legs out, knees straight and feet pointed up toward the knees. Tighten your thigh muscles and turn your feet out as far as you can, holding for ten seconds. Now turn your feet in as far as you can and hold for ten seconds, keeping your thigh muscles tight for the entire exercise. Do three of these sets.

Foot Press
Either sitting or lying down, put one foot on top of the other and pull up with your lower foot as you push down with the upper foot. Hold that for ten seconds, and then switch feet and repeat. Try five sets of these.