Yeah I certainly don't treat uni as a fashion show, I live in jeans and whatever top. I go for optimum comfort at uni, not fashion. No one Ive come across gives a shit.
About the friends thing, Im a person who doesn't mind cruising around the place on my own, Im not at uni for the social side of it, Im there to get in and out as soon as possible. Having said that you do meet some fantastic people at uni, who you will generally have quite a bit in common with because you are studying the same thing. First semester was a bit of a drag because I knew absolutely no one and Im fairly shy so it seemed like everyone else was becoming friends with ease and I was still a nigel. However in second semester I did some group work with a group of fantastic people who are now some of my best friends.
There will be the groups who haven't let go of school and keep to themselves--theres one group in my course who went to school together and are now all studying the same thing. They sit under the same tree everyday, and still seem to act as though they are in high school.
I guess in the end you've just got to let it come naturally and not force it. There will be people you like, and people you don't. Everyone is trying very hard in the first few weeks to be friendly and such, so just talk to heaps of people until you eventually find someone you get along with naturally.