By being aware of some of the differences you lessen the impact of culture shock and you make your life considerably easier.  Here is a list of some of the more overt cultural differences of Western culture in relation to Chinese culture:

Food Etiquette

Food etiquette in China is differnet from other culture. Watch what they do. You will be amazed. Slurping and reaching for food is totally acceptable as it removing food from one's mouth and putting it on the table. Note that playing with chopsticks and making faces at the food (no matter how disgusted you might be) is not acceptable. Showing this emotion is considered a loss of face. Also note that going "dutch" is seen as unfriendly. If you offer to pay for everyone's meal it will develop your relationship with him or her or them, even though they may not let you actually pay.

Crowds

We might as well address the one thing you HAVE to get used to. People. Ands lots of them. If you choose to travel or go out you will be exposed to crowds. On public holidays the masses of people will become readily apparent as you shop with 1.5 billion Chinese. Don't expect people to wait in line/queues. There is very little sense of personal space.

Visiting a Person's House

If invited to a Chinese person's house, which will happen, always take a gift of fruit or flowers. A pre-made basket of fruit costs about 30RMB. A bag of oranges or a bunch of flowers only costs a couple of Chinese RMB. Red flowers are good to take. White flowers are only used at funerals. I always have a supply of indian candy smoked salmon that I bring along with me as a "gift from home" which always goes over a treat. It's a lot more expensive that 30RMB. I buy online at www.salmonexpert.com Fish is also a good gift. Learn more about the food culture and symbolism in China in the Food in China section

Smoking

Smoking is seen as a manly thing and very few think of it as a health threat or as offensive. Often people will smoke in restaurants with little or no regard for smoking or non-smoking sections. Chinese men constantly offer cigarettes and alcohol to other men. The type of cigarettes a person smokes establishes a class system. To decline an offer of a cigarette or alcohol say gently, "Wo bu hui. Xie xie."

Tipping

Today, attitudes towards tipping are changing. Although the practice is not officially recognized, tips are now frequently offered to and accepted by travel guides, tour bus drivers, porters and waiters in top-class hotels and restaurants. However, tipping is still not expected in most restaurants and hotels. Consumer taxes are included in price tags on goods but big hotels and fine restaurants may include a service charge of 10% or more.
Physical Contact/Holding Hands in Public
Chinese are not big on public displays of affection, you will rarely if ever see couples kissing or making out in public. Shake hands but refrain from hugging, kissing, winking, patting or making physical contact.

As a "friend", you will find that men will hold hands with men and women will hold hands with women and walk on the street. This may be "weird" in the west, but it is a common, friendly practice for young people/adults in China. You may even have a friend of the same sex try to hold your hand at some point. It's a very weird feeling.
 
Eye Contact

In Western countries one expects to maintain eye contact when we talk with people. This is a norm we consider basic and essential. This is not the case among the Chinese. On the contrary, because of the more authoritarian nature of the Chinese society, steady eye contact is viewed as inappropriate, especially when subordinates talk with their superiors.

Chinese students are not brought up to maintain constant eye contact with their teachers. Eye contact is sometimes viewed as a gesture of challenge or defiance. When people get angry, they tend to maintain steady eye contact. Otherwise, they keep talking looking elsewhere or nonchalant. Also, try to avoid physical contant and eye contact with the opposite sex.

Bowing

Bowing or nodding is the common greeting; however, you may be offered a handshake. Wait for the Chinese to offer their hand first.

Spitting

Not one of the most beautiful elements of Chinese culture but definitely a predominant one. Many Westerners are put off by the "horking" and violtent phglem raising efforts of Chinese people. I was most surprised when someone behind me at a traffic light did this big horklike sound (I am only guessing you can imagine this - try it now - saw hawk but now pretend you are gurgling while you say it and clear your throat at the same time. That's what I mean by "hork". Well someone did this behind me and I turned to give him a stink eye and saw that it was one of the most beautiful girls I had ever seen in China... wow. Not impressed. Sptting and littering is normal yet frowned upon. Even in a restaurant spitting and littering occurs. It is important to ALWAYS consider where you sit or put your bag down and I highly advise you NOT to walk around barefoot.

Teeth

Not sure where to start here. There is no fluoride in the water. There are few dentists. Teeth are ugly here. Imagine the UK a hundred years ago... teeth are like that. As a result, breath has a tendancy to be rather putrid too. Deal with it. Good luck

Inviting People Home

You are definitely welcome to invite Chinese people to your home. Expect that if you invite them that you will be required to supply everything, just the same as if you invite them to dinner in a rstarant. One thing to remember, it is best NOT to invite a Chinese person to your home country. Travel is not easy for Chinese people. If they want to go to your home country they will bring it up.

Age

Be prepared to be asked your age, or why your not married or don't have any children. This is not considered prying but rather considerated friendly and expressing interest in your life. Maybe a little prying too.

Chinese Hosts Offering Something

Usually when a Chinese host offers a guest refreshments, if the guest declines, the host will ask again twice. Remember this if you entertain at your place. If someone declines they may really want something so you should really ask a couple more times. It makes it look like you are really concerned with their comfort... I know... Most guys don't have the patience for this sort of stuff. Speak your mind so we can move on to new topics faster... slow down everybody. Life doesn't have to move so fast. Consider this scenario and then watch or participate in a Chinese Tea Ceremony. Quite remarkable.

Animals"pets" in China

Animals are not treated with kindness in China. Many of our teachers have adopted pets during their stays which is great and humane and all those good things but realize before you judge the Chinese that they have not yet established a "pet culture". Animals are just there. It's hard but try to overlook the unkindness.