I wasn’t in a quad, but for dorming in general, whitespace has good recommendations. I keep a shoebox of ibuprofen, cough drops, hydrocortisone cream, a thermometer, etc.-- the basics-- which is really nice when sick, because nobody wants to haul themselves to CVS or pay a premium at Wollaston’s. Earbuds, power strip also important. For me, investing in a really good pillow made all the difference too.
For what it’s worth, it never hurts to have something like Cards Against Humanity on deck, it’s a good game to break the ice as it’s easy to deal new people in/out and it’s pretty funny. Some of the guys on my freshman year floor had a pretty big TV and XBOX set up which always attracted people to their room. Another girl had made banana bread at home and advertised it on her whiteboard; she’s one of my best friends after meeting her from that. They might be a little gimmick-y, but it’s easier for some people than just introducing yourself. Kind of on that note, if I could give one piece of advice for freshman year, it would probably be to not “group” yourself immediately. I saw a lot of folks who tried to form tight groups and not make other friends, and when those drifted or dissolved for whatever reason a bit into the semester it was much harder for them. Cast a wide net and winnow down later.