I have a lot of sleep issues. I currently am prescribed a strong hypnotic which does work well but there's no way I can advise someone to take medication, unless it's your last option. Some things you can try are: no tv or computer an hour before you go to bed. The lights are stimulating your brain to keep you awake, it needs time to cool down before attempting to go into unconsciousness. Exercise in the day, but not too close to sleep time. Some gentle yoga or stretches can be good. Take a bath or shower, keep your bed and sleeping space clean and tidy. Read a book. As the person above said, certain tea's or warm drinks can really help some people. Valerian root is a natural plant with a sedative effect, but this is borderline medication imo, idk, you may want to ask your dr about it or research a bit.
Oh and something i like to do if i can't sleep is to find a comfortable sleeping position and say to myself i'm not allowed to move until i count to 500. I then race in my head as fast as I can to 500 and am allowed to adjust myself. Then i go to 1000 and reset if necessary. When you start forgetting what number you're on, which hundred, which ten etc, you are falling asleep.