There are many techniques to help you sleep. You need to learn to relax, and practicing the art of meditation can help this. There are some herbal remedies to help you, including Chamomile and Valerian. You must deal with the reason that you are having trouble sleeping, it may be too much stress or a troubled conscience. Not enough sleep can make you very sick and weaken your immune system. You must address the problem at hand. Try to keep a positive attitude about your life, and stay happy. Keep smiling, and relax before bed: let it all go.
If this fails, try Melatonin.
Take care of yourself. But, at the end of the day, when it is time to sleep, you need to find one thing to focus on that is calming, relaxing, and pleasant. Create a calming environment and have images around you to reinforce your environment.
Go to your local GP. They can help you with curtain issues which the sleep is resulting of. This could be you diet which you are consuming. For example if you eat alot of sugar, caffeine ect.
If you notice you do have these kinds of foods at night try and go with out eating for 2 hours before u plan in which to sleep. This will give your body time to get rid of your energy which will let you sleep peacefully. (This will not work for all)
You can also try drinking a warm milky drink at night it relaxes your body and gives you the erge to drop off in to a pleasent sleep.
Reasons you might not be able to sleep.
Stress. Diet. Lack of iron. Unactive Fireriods. Anxiety. Or health issues such as semi insomnia which will be unlikely but you never know.