I'm one of those that falls asleep practically as soon as my head hits the pillow. But sometimes, for whatever reason, I can't sleep! Usually it's because I've got too much on my mind. I try to keep a stress-free life, but things creep in and get to me, and chip away at my sleep.
At one point in my life, I thought I had to get everything done before I could go to bed, so I was up until 2 am some nights. Then I would sleep until 10 am. Recently, I reversed that habit and get up at either 4 am or 6 am (depending on how much I have to do) and go to bed much earlier. This schedule has also helped me get some alone time, which is VERY helpful since I am a single mom who also homeschools. I had read somewhere that going to bed earlier and getting up earlier is a more natural schedule for our bodies and I think this is true. I feel much better. And I know if I don't finish something, I will have time in the morning to do so. Just changing the timing seems to have given me three extra hours in the day. It's wild! If you have control over your schedule, it might be something you want to look into if you aren't doing it already.
In any case, this might help you get the sleep you need if you are lying awake at night, tossing and turning, and watching the hours go by. Happy sleeping!