I used to suffer with insomnia so heres some tips to help you sleep but keep in mind they come with sacrifice. Don't use the internet or play any games 2 hours before you go to bed. The light projected from the screen messes with your eyes which puts stress on them and the stress on your eyes keeps you awake.
Don't drink anything with caffeine in it after 6pm, thats an obvious one aye.
Reading 10 or so pages of a book relaxes the mind and makes you tired.
Try not to think when trying to sleep. This is were counting sheep comes from. Counting numbers occupies your thoughts which stops you from thinking of the things you otherwise would have thought of.
Also have you tryed sleeping tablets. They work like a charm but they are very addictive so be warned.
Other sugestions is to try and get up early every morning. If you get up around 8am every morning by the time 12am at night hits you'll be trying to keep your eyes open