In our house I would sing to the kids Good Night Ladies/Gents What Will You Dream. I had the kids tell me what they wanted to dream about that night. It always had to be positive and it was a way for them to take some control over their night time thoughts, but I also told them that it was a way to work out problems, practice for some situation or event they found difficult. Often in the morning they would say that they thought of something, and when they came home from school would surprisingly tell mom that it worked.
I know for myself I have gone to sleep to deliberately work on some solution, and here is science to let me know I am not all wet