You don't! Lol!! I was literally miserable my whole pregnancy. There is no way at all that you can get comfortable. They say laying on your left side is the best. That is what I did all of my pregnancy. It was still hard to sleep. There is just no way to get comfortable. It sucked so darn much.
Pregnancy pillow is your best bet and maybe a kind partner who will rub your back here and there but it gets harder as you go.