Find a good book on the subject and read it. The Chinese are very open to foreigners and will show their best to you. Be careful when visiting students that you do not ask for anything unusual. Their income is often quite strained and your visit requires them to buy the good food (ie expensive!!) so be sensitive. Be gracious and accepting.

Be careful about saying you like something because you may end up with it. This is how I got two guinea pigs in January 2002. All I said was they were cute and soon I had 2 companions on my 8-hour train trip home. I finally got rid of them in July 2003.