I have suffered insomnia for many years. Never drink coffee or tea after 4pm. They both contain caffeine, which stays in the system for hours. You could try eating a turkey and lettuce sandwich, with a glass of warm milk, all of which are soporific. I have tried many things over the years, to no avail. I sometimes find that I can nap for an hour in the late afternoon, when my Dad is asleep, but only if I read for about an hour first. It's very difficult I know and my suggestions will probably be of no use, but it's worth a try.