I don't have a general sleeping problem. However, I find that reading in bed for around 15-30 minutes before I try to sleep helps clear the mind of any repeating thoughts. (I read something not taxing, generally fiction). I find this takes your mind into a slower mode. I have also found in the past that casually counting backwards slowly in my head, (down from 5 to 1), and repeating this over and over, works for me.
I think keeping to a routine can help a lot, (including at weekends). Stay away from sugar and caffeine about 3-4 hours before you want to sleep. Generally, I find that if you need sleep that bad, you do fall to sleep. And I remind myself, that even if there is something important to do the next day, you can usually function without any sleep for a at least a day.