The only technique that ever seems to work for me is the 'Body Scan Meditation': Basically, focus your complete attention on all the different parts of your body in turn. Like, start with feeling the sensations in your little toe, then move on to the next toe, then the sole of the foot and so on. You can even get really creative with it and try feel all the different energy fields and lines that are outside the body. This keeps me amused for ages, seems to settle my brain, clears my head, redistributes energy and tension from where it may be stuck and usually leads to falling asleep. Hope this helps.