Wear high quality shoes. As a runner, it is wise to think of your running shoes as an important investment. Running is a tough exercise, and it places a tremendous amount of strain on your body, most notably your knees. Wearing a high quality pair of running shoes in the correct size goes a long way towards making you a more comfortable and capable runner, as well as lessening the impact and shock placed on your knees with each step. A high quality shoe offers a firm, well-padded sole, sufficient in-sole flexibility, and enough side tension and support to prevent your ankle from rolling excessively. A quality shoe is not necessarily an expensive shoe. Adequately evaluate and try on each individual pair of shoes to check for functionality and performance, regardless of price.
Run on softer surfaces. Make a conscious effort to run on the grass instead of on the asphalt or pavement. The intense pounding that running places on your knees is greatly exacerbated when you run on hard, non-flexible surfaces. Other options include running on the sand at the beach, or even running at home or at the gym on a treadmill.
Lose excess weight. Runners who are overweight place an extraordinary amount of stress on their knees. Running is tough enough on the knees without adding excess body weight to the equation. For every pound of excess body weight you lose, you reduce the load placed on your knees while running by about 3 to 4 pounds.
Warm-up. Stretch your knees and lower body prior to starting any run. Whether that means doing squats, jumping jacks, deep-knee bends, or any other type of stretch or warm-up, always adequately loosen up and stretch your knees to prepare them for an impending run. A knee that is flexible and loose is a knee that performs better and be less likely to be injured during a run.