I hate it when your mind gets wired and you end up lying there in bed with what feels like a train running through your head. My mum once told me about a sleeping exercise several years ago and I still use it to this day and it works the majority of the time.
What you do is imagine you are at the top of a flight of stairs. There are ten steps leading down. Imagine walking down these steps in your mind. Start counting down and matching it with your breathing. Breathe out on ten and by the time you get to one you have your last breath out. When you get to the bottom of the flight of stairs there is an old wooden trunk. You place everything that is troubling you into this solid trunk and lock it up. You chuck the key in your pocket and walk down the hall. At the end of the hall there is a door that opens up onto whatever you want. My favourites are walking along a beach with golden sand or walking through the woods on a still morning.
I hope I have written that in a way that makes sense. It is very hard to explain to someone without being there in person.
Natom.