Q Learning how to be a respectful roommate (and practising the skill) is the gift that keeps on giving. Learning how to respectfully cohabit is something that will serve you for the rest of your life—in relationships, work environments, really any time you need to share a space with other humans.
Mastering it can be tricky—different folks have different ideas about cohabitation and, sadly, cleanliness—but here's a few basic jumping-off points to help you become a dream roommate.
Controlling volume appropriately (we're talking music, sex, Netflix) is just polite. Not ploughing through your roommates' pantry staples (especially if they have special dietary needs or splurged on some fancy French marmalade) is crucial. Some households share food, some households label obsessively. Try to be the type of person who's OK with someone using some peanut butter or some of your shampoo, but avoid getting into a situation where you're the only one who buys toilet paper, for example. It's a delicate balance, but it helps if you reframe every annoying/enraging roommate situation as an opportunity to work on ye olde communication skills and a way to get comfy with constructive conflict (the most important life skill of all, even more important than flossing).
While the variations between roommates can be as numerous as grains of sand on the beach, there's one thing that unites all: household chores. Be that roomie. Start a chore wheel.
It can be as detailed or simple as you decide to make it, but if you are living with some real rigs, it's best to err on the side of "more detailed."
Dishes are always outside of the chore wheel, since they can't be done once a week. It's a fact of life that no one believes they use as many dishes as they do. What starts as "I just wash the dishes I use," inevitably translates to "I wash my pots and pans after I cook but I almost certainly do not wash my random coffee spoons or toast plates." Washing your own dishes will never work, and never has worked in the entire history of having roommates.
But there's an elegant solution: Each roommate gets a little tag with their name on it. These tags are hung on a single peg in the kitchen over the sink. Whoever's name is in front does all the dishes, then they put their tag to the back of the pile. This way, it's up to each roommate how many dishes they have to do. You can do the dishes as soon as your mug hits the sink, and bam! To the back of the pile you go. But, if you're a lazy dish-doer, your inaction is punished by an unnecessarily large quantity of dirty dishes. And the worst part is you only have yourself to blame.
However, this method is not without flaws. If you have roommates who don't seem to exist/whom you never see, or you have a total dick roommate who does the dishes, puts their name to the back of the pile and then cooks a gigantic feast using all the pots and pans, you may need to recalibrate.
Trust, it's worth the effort to be that amenable roommate, all of your future roommates/partners/colleagues will thank you.