When sleep eludes me and I find myself thinking of troubles, worries, and all that needs to be done the following day, I divert to my novel/s in progress.
You'd be surprised to find how many great plots you can come up with as you wait for sleep to come. For some of us it might be a good idea to keep a pad and pencil on the night stand to jot them down, lest they be lost to grogginess after sleep finally comes.
Thinking of stories and plots might also help prevent bad dreams. After all, most dreams are about the last things we think about. Who knows? A dream involving our stories in progress might even be a great inspiration!
So, if after the warm milk, relaxing music, and ear plugs, you are still a bit restless before sleep, think of what your characters will do next. What changes can improve the plot. How to make the reader want to keep turning the page.
And last but not least, think of your waking dream of getting that book published. Imagine it as a reality and you will fall into slumber with a smile on your face.