Sure, finals weeks is tough, but have you tried living in a dorm room with another human who doesn't wash their towels more than once a semester?
1. If your roommate's cell phone alarm is going off and they're not in the room, call the phone.
"It'll disable the alarm." —mmmikaykay
2. If you abuse the snooze button and don't want to annoy your roommate, place your alarm clock at the foot of your bed so you have to physically stretch to turn it off.
"This makes waking up a breeze." —avauk12
3. Keep a dry-erase board in a common area.
"You can write the costs of shared items, courtesy notes for when a small gathering of people is going to happen, requests of total privacy, reminders to get more paper towels, etc." —user
4. Don’t lock them out of the room while they’re showering.
"Try to make a habit out of considering where your roommate is and whether they are likely to have a key on their person when you go to lock the door. (I’ve locked my roommate out during her shower on more than one occasion. I’m working on it.)" —samchai
5. Establish a "free shelf" for shared items instead of fighting over what's communal.
"Buy all your own stuff, but if something is about to expire in a few days, or you bought something new but decided you didn't like it, just chuck it on the free shelf. It encourages sharing and limits waste. Even if one roommate never contributes, it never causes drama as it was a waste anyway." —Liquid_Sky
6. Don't ever offer up your roommate's bed without their permission.
"Example: If your roommate's out of town and you have friends over. And if you have to borrow their bed, then you need to change the sheets the next day." —knewtc
7. Take a picture of anything that's yours that's going to be used communally.
"That way, when it's time to move out or if things end badly, if someone is trying to take your stuff, you'll have proof it's yours. If it ends well, you'll have an easy time figuring out what you need to pack when you move." —sampsonite137
8. Try to avoid discussing chores/complaints within the first 10 minutes of someone getting home.
"Let them reset and settle in! This rule helped us avoid a lot of nastiness in roommate disagreements, and it was nice to gently remind people if they started in — 'Hey, 10-minute rule!' — and then you can discuss it more calmly later without so much emotional baggage from dealing with the outside world." —doinscottystuff
9. Don't use the sock-on-doorknob policy unless it’s been explicitly OK’d by your roommate.
"Your roommate should never be kept out of their room without at least some warning. If you need the room to yourself, ask your roommate beforehand or develop a system that both of you are comfortable with. And, in general, be courteous — don’t abuse your roommate’s willingness by constantly demanding the room for yourself." —samchai
10. Never leave your laptop out in the open.
"When I was in college, I must have heard two stories a year about one person leaving their laptop on a table, and then coming back to find their roommate spilled water on it. Or if they left in on the couch, their roommate sat on it and cracked the screen. No matter what, it was a very difficult conversation about who is on the hook for replacing the $800 device. When you aren't using your valuables, put them in a case on your desk, or anywhere they won't get damaged by accident." —Throwawaywts
11. Have your roommate write down their emergency contacts, medications, or allergies.
"In the event of an emergency, you can call your roommate's family or pass the pertinent medical information on to a dispatcher or paramedic." —MississippiJoel
12. Get a desk lamp — no one wants to be kept up all night because you procrastinated your final paper.
"And get two sleep masks: one for you and one for your roommate. Communicate when you'd like to use them. They can be a godsend when someone has to pull an all-nighter." —WinterCharm
13. Try crinkling a bag for a few seconds if your roommate is snoring loudly.
"I usually get frustrated with my roommate's snoring, and have tried everything from slamming my palms against the wall to yelling his name. Usually he never wakes up, but I just found out that crinkling a little bag of chips or candy will make enough noise to wake them without being too rude." —joeltrane
14. Live by the two-minute rule: If you can clean/organize it in two minutes or less, do it right now.
"By following it, I can clean up almost any mess I make right away before it becomes a problem." —DredfulDisaster
15. Don't leave passive-aggressive notes.
"I have found in the past that any notes left to each other about messes, being too loud, or other inconsiderate issues always come off meaner than they're intended. My current roommates and I are trying a 'no notes in the kitchen' rule, so that if we have a problem, we have to talk it out in person and there aren't miscommunications." —ilovemathematics
16. Always use headphones.
"Unfortunately, not everyone enjoys the music you listen to or whatever you’re streaming on Netflix. No, turning the volume down isn’t good enough. If you can hear it, they can too. Headphones. Please." —Adeelmna
17. Above all, you don’t have to be best friends, but at least play nice.
"Since you'll be near this person for a majority of your time, it’s in your best interest to get along with them. Even if they aren’t the sort of person you’d freely hang out with, at least make an effort to get to know them: their name, where they’re from, their hobbies and interests. Be courteous." —Adeelmna