美国校园文化以及日常生活礼仪（尽量详细些·）

There are so many things, I don't know what exactly you are looking for. But in general -

1. Look at people's eyes when you talk to them.
2. be courteous, develop the habit to say "please" and "thank you.", smile often.
3. respect other people's privacy. Don't ask too many personal questions unless you know them really well (eg. salary, religion, sexuality, etc.)
4. respect other people's personal space, don't lean too close unless you are good friends.
5. Don't talk too loud in public spaces.
6. when you need to open a door when leaving a classroom (or other spaces), hold the door open if there's someone behind you.
7. be pride of your nationality, but do not "show off" or "brag" about it. (eg. don't keep saying the beijing olympics is the greatest ever...)
8. don't be too shy. if you don't understand something, ask. If you don't ask and keep everything to yourself, you could be perceived as "aloof"