My thing is choosing a subject, and then I run through the alphabet, soming up with things realted to the subject on each letter. For instance; fruit, weird names, book/film characters, cities, things I hate, things from my childhood etc. Works rather well actually. Or I'm thinking of one of my favourite books, and I think of what actors I would cast if I were to make a movie of that book, and I could choose whomever I wanted. Or I hang my head "out on the edge of the bed" until I get dizzy, and when my head is back on the pillow, it feels so good that I almost fall asleep instantly. And if all this fails, I try to remember dialog in a film I've seen a lot, or the exact words in a favourite book.
Hope this will help someone to get some sleep if they're not aslep already...
Hugs, Rowleene