I rarely have trouble dropping off to sleep at the end of a busy day, but I often have trouble getting back to sleep when I wake up in the middle of the night.  I think many people struggle with this especially when there is a lot on your mind.  I have found an extremely valuable tool that works for me 90% of the time.  It may not work right away for you but I encourage you to keep practicing and your brain will get used to the idea that this means it is time to sleep.  This idea came from Dr. Andrew Weil.

Here is the exercise:

Take a deep breath through your nose for four counts, hold it for 7 counts and release your breath thru your nose to a count of 8.  Repeat at least four times but for no more than 8 cycles.  That’s it.

Sounds simple, and it is, you just have to practice it.  You can also use it for immediate stress relief during the day.  The reason it works is that we are influencing our involuntary systems by helping them to relax.  We do it deliberately for a while, then your body will start to remember that this is the relaxing response. In 6-8 weeks you will notice changes and maybe sooner, as it didn’t even take that long for me.  Good luck!