Exercise regularly.

Try to create a positive habit of exercising for at least half an hour every day. This can be anything from taking a nice walk to challenging yourself through tougher exercise or sports. However, avoid pulse-raising exercise too late in the evening, when your body needs to start winding down. 

Why it helps:
Physical fatigue makes it easier to both fall asleep in the evening and stay asleep through the night. Exercise can also reduce the need to use sleep medication. If you exercise regularly, you also learn to tolerate a reasonable amount of stress without raising your cortisol levels too much, which also contributes to better sleep in the long run.