no alcohol, no coffee after 12:00, try to eat less(caloric food) at dinner & try to eat no closer than 3h before your sleep, make sure the room you sleep in is

no alcohol, no coffee after 12:00, try to eat less(caloric food) at dinner & try to eat no closer than 3h before your sleep, make sure the room you sleep in is fully dark, make sure you have comfortable temperature (if you are rich, you may as well get that ultrafancy mattress that regulates the temperature), make sure pillow is comfy, not too hard&not too soft