1. Caffeine. While drinking coffee or soda in the morning helps you get a shot of energy for the day, it may keep you awake late at night.
2. Alcohol. A common belief that a beer or a shot puts you to sleep is a myth. Like caffeine, alcohol is a strong stimulant, and it is more likely to keep you awake than make you sleep.
3. Heavy dinner. Despite feeling sleepy right after a meal, you will not sleep well if you eat a lot right before bedtime. You need to give your body at least 2-3 hours to digest food before going to bed. Otherwise, it won't be fully relaxed and ready for wholesome sleep. Same applies to the consumption of liquids. If you drink a lot of water before bed, you will have to take bathroom breaks in the middle of the night.
4. Hunger. This is another extremity. I don't like eating a lot late at night. At the same time, it is annoying to wake up hungry. Therefore, I try to eat something light, like yogurt or fruit if my stomach growls before bedtime. That usually ensures that I sleep better.
5. Irregular schedule. When you wake up and go to bed around the same time, your body gets used to this routine. You feel sleepy during the same hours. For this reason, having an irregular schedule is bad for your sleep because your body will not be able to quickly adjust to your ever-changing hours. Try to maintain a regular sleep schedule, and you will sleep better and deeper overall.
6. Uncomfortable temperatures. If your room is too cold or too hot, or your blanket is too thin or too thick, you have to make adjustments. There are even special blankets for couples that allow them to set temperatures on each side to help people who have different heat/cold tolerance from their partners sleep better.
7. Worries. These are the hardest to get rid of. They often keep us tossing and turning. Try meditation or any other relaxation technique to put your worries aside. Tell yourself that you will take care of your problems when you get up.
8. A snoring partner, or any other type of noise. If you're sensitive to noise and cannot stand hearing your neighbors' pillow talk, use earplugs. I prefer silicon ones, those that swimmers use. They cover your ears completely and isolate most noises.
9. Lights. This might be a problem if you sleep during the day, or have a street light right by your window. If that's the case, try getting blackout blinds or an eye mask to keep the light out. Keep in mind that you might not be sensitive to all of these sleep-disrupting variables. Therefore, you should listen to your body, take a note of what bothers you the most and work on eliminating it. Only you know what is the most comfortable environment for you, and it is up to you to set it up for better sleep.