Work worries, family issues or relationship problems often cause loss of sleep, and sometimes run into a vicious circle where you end up making a bigger issue out of a small issue because you've slept badly.
Try the worry chair: an hour before going to bed, sit yourself down comfortably and think clearly about everything that's worrying you. Then get up and leave your worries behind in the chair. Strange, but it works!
Yoga, breathing exercises or a few minutes of meditation are also great for winding down and clearing your head.
Finally, as soon as your body sends out the first signs of tiredness (yawning and burning eyes) don't wait a minute longer: to bed with you!