Primal made my sleep worse at first, but the addition of magnesium and elimination of ALL caffeine was the solution for me. I use a topical magnesium brine about an hour before bed to make sure i get enough. Are you getting a good dose? Do you have any caffeine in your diet?
The other hint I have heard was to take a teaspoon of honey before sleep. There is also a book that suggests having a protein/carb combo snack immediately before sleeping.
You could also try taking L-theanine before bed - it is supposed to be very helpful for people with racing thoughts at night.