Typical Warm up exercises include:

· Gradually increasing the intensity of your specific sport. This uses the specific skills of a sport and is sometimes called a related warm-up. For runners, the idea is to jog a while and add a few sprints into the routine to engage all the muscle fibers.
· Adding movements not related to your sport in a slow steady manner: calisthenics or flexibility exercises for example. Ball players often use unrelated exercise for their warm up.
· Which to choose? The best time to stretch a muscle is after it has an increased blood flow and has increased temperature to avoid injury. Stretching a cold muscle can increase the risk of injury from pulls and tears. So you are better off doing gradual aerobic exercise before stretching. Keep in mind that the best time to stretch is after exercise because your muscles are warm and pliable with the increase of blood in them.Make sure your warm up begins gradually, and uses the muscles that will be stressed during exercise.
· Keep in mind that the perfect warm up is a very individual process that can only come with practice, experimentation and experience. Try warming up in various way, at various intensities until you find what works best for you.