This is really important. Not confronting this one will doom you later. You need to make some choices about sorts of people, gender, smoking, drinking, (particularly) drug use and noisiness and cleanliness. There is a particularly strong issue around cleanliness and the cleaners won it hands down about five years ago.
If you're happy with dusty TV screens and scuddy toothpaste around the bathroom taps (this can mean you are male or in the medical profession) then you hold a minority belief that isn't even given the light of day. Actually there is some evidence emerging that home hygiene is giving rise to immune systems that are bored adolescent boys that go on to create mischief of asthma and eczema. Try rehearsing this theme in your living room when you didn't clean the toilet.
Your academic views about cleaning need to be honestly explored when you go to visit your prospective flatshare. Flatsharing in property is a delicate pastime and early thought pays big dividends. It is at least as big a consideration as the quality of accommodation itself.
Its a good idea to take a long look at yourself in your smart phone screen and decide what sort of person you are. Are you extrovert, love leading a group and well can be a bit noisy, or do you rather detest and resent these qualities in people and prefer to be at home gardening or stroking the cat ?