Most dancers have a reasonable amount of flexibility due to the nature of their work, however it is important to think about timing, the type of stretching and how much to do. Stretching is ingrained in each dancer's life in order to improve flexibility, whether it comes naturally or not. Some dancers can become frustrated if their stretching efforts don't pay off, but there are some tricks to help the stretching along a little!
There is lots of research which has been done to show that the timing of stretching is vital. Prolonged and excessive stretching before a dance class or performance can be detrimental to muscle strength and power, and can even increase the risk of injury. Make sure you do a thorough warm up before you do any stretching: stretching the muscles when they are cold may mean they won't 'fire' properly when you need to use them. Stretch after class to increase flexibility, when your muscles are completely warm.
How you stretch also has an impact: many dancers focus on passive stretches, where the limbs are held in one position and gravity is used to increase the range of motion. This type of stretch is less likely to achieve true increases in muscles length and may even stress the joints and ligaments. Contracting the muscle against resistance when taken the point to where a strain is felt is more beneficial, as the limb can then move further into the stretch. Ballistic stretching (bouncing in and out of the position) is not recommended.
As well as stretching it's important to cool down properly after classes, which also decreases the risk of injury and improve muscle recovery. Keep the muscles warm after you stop to ensure you don't get stiff and the muscles cool down gradually.