I used to use the Guinness system. Lie and think of a pint of cold Guinness for exactly three minutes. If you don't fall asleep in that time get up and drink one then go back to bed. Repeat this ad nauseum. I guarantee that you will eventually sleep.

Now, the waking is another matter :-).

On a more serious note, as I get older my sleep patterns are not as secure. I wake more than I used to and sometimes have difficulty in "dropping off". I find that as long as I feel OK I am content to let Mr Sandman catch me when he can and try not to allow it to become an issue. One trick is to try and deliberately stay awake for an hour.

Dave Wynn (A.K.A. Spot the Dog)