You will arrive at university in early September with a suitcase, a set of expectations, and an anxiety hangover from three months of not knowing what to do with yourself. That is normal.
Orientation week (迎新周) is a strange, packed period. Do not sign up for every club that has a table. Pick two — one that matches an existing interest, one that scares you a little — and let the rest wait until the second semester.
Roommates are assigned. You will probably not choose them. Kindness in the first week pays enormous dividends over four years. So does not judging anyone's home province.
The academic pace is looser than senior year of high school, but the reading load in humanities and the problem sets in engineering catch up with students who mistake looseness for lack of demand. Do the first month's work in the first month.
Homesickness is real and it usually peaks around week three. Call home more than you think you need to. It helps them and it helps you.
You are through the gaokao. The rest of your life is not an exam. Try to remember that.