I have been an insomniac on and off for years now, but I seem to settle a lot easier now. Part of it is my frame of mind. I just lay there with my mind goes a hundred miles and hour tossing and turning but sleep seems to settle in faster and more calmly. ALso not having coffee after 5pm has helped.
I try not to think too much or I think to get those thoughts out of mind and if no luck write them down if need be so the thought is now on prepare ready to consider in the morning.
Natural remedies to help -
Lavender - find a spray with real lavender and spray your pillow before bedtime.
Yoga or meditation - gentle yoga or stretching followed by simple meditation for 5-10 minutes paying attention to your breathing only.
Valerian - to help improve a deep sleep, speed falling asleep and quality of sleep.