I have no regular sleep period. It's 5:17 and I am up and ticking, not a living soul here on the Forums. I find that it does no good to force the issue and use the time to do whatever I would normally do at a more sensible time.
If you are having worries that keep you awake, a good distraction is visual imagery. It goes something like this: Everyone has a good recollection of the house they grew up in as a child. For some reason, early images are more deeply impressed on the consciousness. Imagine you are walking up the steps to the front door. Try to picture as many details as possible: the crack in the step, the way the door knob looked, etc. Continue through the door, always eliciting as much detail as possible, and visit the other rooms of the house.
Other relaxation techniques include tightening and relaxing your muscles sequentially from your toes on up. Tense them as much as possible and allow them to return to a relaxed state.
Another self hypnosis riff is to draw in a deep breath, and imagine as you let it slowly out that you are descending a set of stairs: count...one.....two....three....four, and have it in mind with each step you are becoming more relaxed, more relaxed, more relaxed. Repeat this over and over and soon you will drop off. This works every time for me, and it does because I have programmed myself that it will. It is most useful!
A repeated phrase or mantra (e.g. Om Mani Pade Aum) chanted repeatedly in your mind will cut off internal dialouge and leave no room for worry.
These techniques used in tandem with Trashcans good advice will serve you well. Also remember rest and sleep are two different qualities: you can rest without sleep if you don't tense up and fret about not being able to sleep. If you find you can't stop thinking, then you can always get out a book and read. This will distract the body and mind enough for the natural processes to take over, and if your body is tired sleep will follow. One of the worst things is to lie awake worrying about the fact that you are not sleeping, looking at the alarm clock ever 5 mins. and sighing! The body can't rest with such tension present. Worry and stress are our enemies. I suggest if you are a worrier, that you reserve a portion of time prior to sleeptime to indulge in worry, and do so only at this time. Don't worry during the day, and if you find yourself doing so, tell yourself it can wait until the assigned time: between 8 and 9 PM. Then go ahead and worry about every last flippin' thing you can imagine. At 9 PM, stop worrying!
Hope this helps. Yawn.