I can't stress exercise enough here. Exercise is paramount, especially for people who's daily jobs that require lots of hours sitting on a chair. You simply are not tired enough.
Food, try to eat light by night. Say you go to bed at 11 p.m., you should eat your last meal (light meal...) at 8 p.m.
Don't sleep during the day, you should get a good sleep 7 to 8 hours during the night.
Avoid TV-screens, movies and any kind of digital devices after 10 p.m... Grab a book, read for an 1h before going to sleep.
Try to refresh the air in the room, like open the window for 15 minutes before going to bed. The coverlet should be optimal to keep you warm, but not too warm or too cold. The body temperature is important to get a good sleep.
Also the pillow and the mattress should be good. You don't want the mattress to be to hard or too soft. Should be hard enough to keep your body straight but not hurt you.
Digital screens lead to melatonin inhibition, which in turn causes all kinds of troubles.. The most visible being insomnia. You could take some melatonin pills, since you're an adult, as a natural sleep enhancement 1h before going to bed.
Everything counts, but the most important thing to get a good night sleep is to get physically tired. Most people avoid that and end up with sleeping pills, which affects negatively their cognitive functions...
If you have any questions, feel free to ask here.
