Flexibility is determined by several factors: joint structure, ligaments, tendons, muscles, skin, tissue injury, fat tissue, body temperature, age and gender. You can quickly improve your flexibility by stretching. Before you start any stretching exercises, make sure your muscles are warm and your body temperature is raised. You can accomplish this by jogging in place, performing a few deep knee bends, rotating your body at the waist, and doing a few giant arm swings.
How long should you hold these stretches? Lots of people seem to disagree about how long is most beneficial. Should you hold a stretch position for only a few seconds, or would it be more helpful to hold it closer to a minute?
Many dance instructors suggest holding each stretch for about 20 seconds, which seems to be a good common ground...long enough to improve flexibility, but not too long to do damage. Some dancers like to count out loud during stretches to make sure they hold them long enough. Counting aloud also helps ward away boredom.
As you perform the stretches, remember that you should not stretch to the point of pain. Obviously, if you are performing the stretches correctly, you will feel some degree of discomfort, but never true pain. You should feel tension in your muscles, but if the tension becomes intense or uncomfortable, ease up before then you overdo it and end up overstretching or tearing a muscle.