One reason for stretching is that it feels good. Another reason is to improve flexibility.
In either case it helps to feel and control your body while you stretch.
For any muscle that you are stretching (whether doing active stretching or relaxed stretching) work at stabilizing one end to which that muscle attaches.
Interested in learning how to feel and control your leg muscles?
Sensational Leg Anatomy includes a series of videos teaching simple muscle control exercises. The whole series teaches you to feel and control the major muscles of the legs from the hip bones down to the toes.
You can also get it as part of the Muscle Control Package(Learn to Feel Your Body)
Muscle control not only helps you to control your body, it also helps you to feel it making it easier to balance, improve flexibility and deal with pain and poor posture.
The dance of shiva is handy if you are interested in improving upper body balance and coordination.