Lets see, the usuals:
Have a hot relaxing bath late on, as the body regulates its temperature to cool back down after sitting in a hot bath, this is what works to relax you.
Avoid stimulants (obviously).
Reading a good book.
Breathing excercises, deep breath in for the count of 3, let it out for the count of 5.
Try and put any worries aside for the night, you cant deal with or do anything once the days over, so try and forget about stuff till the next day.
Relax, and dont get worried or stressed out if you dont fall asleep, this can make it worse. Any res is better than no rest.
Good luck!