I'm with you with this problem.. There are all sorts of things that can help...

* One thing i've been doing though for a long time which helps a little in addition to other stuff is doing this trick of picturing colors.. It's a mind thing that relaxes your mind right down..

Here is how to do it... First i'll write the colors in order..

Yellow
Orange
Red
Green
Blue
Purple
Black

What you do when your laying down with your eyes closed, picture the color yellow and thinking of all things that are yellow. Like banana's etc. Play with them, touch them. You can even go as far as picturing yourself in a completely yellow room with yellow furniture and yellow simpsons characters...
The basis of this color technique is colors have different effect on your energy/resonance levels/body frequency.. Yellow is a very hyper color generally when you lay down for bed, you start with yellow and it is about the same energy that your mind is at.
So for about 1 or 2 minutes you will just picture everything is yellow. The next thing you will do is picture everything in the same way, but orange... I like to transition between each color by pretending i'm walking through a big yellow sheet and as it goes over my head and falls behind, i'm in "orange" world..
Anyway, you do this for 1 or 2 minutes with each colour all the way down to purple and then black...
As you go down each level, you'll find your mind and body start to slow down and relax. With each different colour, your breath will get deeper and deeper and slower. You'll notice this if you get down to say, green, and then picture yellow again, it makes you breath faster and more shallow and it feels uncomfortable..
By the time you get to purple if you've really absorbed yourself in the colours right through, you're mind is pretty slow, and at black, you kind of just following behind your thoughts as the flick past one by one, but you are very much detached from them now and they don't tend to keep you awake/tense/anxious... For some of the colours like green I like to picture really green soft grass like on a wet golf course and you can feel it between your toes etc.. For blue you can be swimming in a really deep blue tropic ocean etc.. YOu get the picture.. Or you can be lazy and just simply picture the colour through your whole vision and not objects.. It's not quite as fun though..

You can vary it by spending 5 minutes or more on each colour, or now i've gotten good at it, i'm able to spend only 10 or 15 seconds on each, and literelly I can drop my heart rate and breath from very fast to very slow just in about 1 to 2 minutes very effectively and am almost ready to settle into sleep while my girlfriend lazying next to me is still buzzing...

* Another thing that really helps in addition to this, or seperate, is to take very very long slow deep breaths.. When you first go to bed, you'll find your breathing fast and shallow. So taking a big slow deep breath in and just holding it, it feels uncomfortable and you want to take a couple of quick breaths straight after it to like, catch up.... But that's okay. Just take another really long deep breath in taking as much time as you can, then hold it in as long as you can, and then release.....
The purpose of doing this is to slow your heart rate down mainly. You're heart is usually going fast when you're mind is racing and you are trying to relax. But after about 5 or 6 of these long deep breaths which should take you probably nearly 2 minutes just for the 5 or 6 breaths, your heart should probably almost slowed to half what it was doing originally...

* My final piece of advice is that there is a pressure point just near your eye that if you press into while your laying down, it actually "grounds" and nutralizes a lot of your thoughts and can cause a very deep relaxation just on it's own....
How to find this pressure point is to place the tip of your index finger on the side of your nose right next to your tear duct. Then move it up slightly towards the start of you're eyebrow, then back in towards your eye socket. You'll need to have your eyes closed to press in there. It's kind of just above your tear duct in the dip between your nose bone and your eye ball... Have your eye closed and just press around that area until your finger finds a comfortable spot to rest..... While your laying down, your finger will press on the eye facing the pillow, so the weight of your head kind of provides the pressure....
I should post a picture with the exact are circled, but you should be able to get it and it seems subtle, but it makes a big difference. You can breath easier and you're thoughts kind of 'pack a lot less punch' i suppose is a way to describe it...

I have about 10 times less trouble sleeping these days doing this stuff than I used to before when my mind would run the show and i'd have no chance...

Good luck!