I've had sporadic sleep problems throughout my life, and even made insomnia a minor specialty in my psychotherapy practice. There are many excellent psychological and lifestyle guidelines you can find in the mainstream media, but I've never seen this idea anywhere, so consider it my personal invention:
Just before bedtime, instead of reading, consider looking at pictures. Art books and children's books are my favorites.
Why does this work? I think it's because the language we use during sleep is the language of images, not words. Dreams are composed of images, of colorful and sometime irrational pictures. Words are the province of the day, when we analyze, plan, predict, and make lists. Words are also the vehicle of worry.
As a cognitive therapist, I help people pinpoint and challenge distorted thoughts -- but this sleep technique asks you to bypass word thoughts altogether! I believe that images, whether of art or fairy tales, help me transition from the daytime world of words to the nighttime world of sleep. Perhaps you would choose different kinds of images -- pictures of nature, or animals, or..... what would be your choice?