Feet: it's rude to point one’s feet at another person. For example, crossing your legs can be rude if you point your feet at another person. That’s why you’ll find that Chinese in business meetings will have both feet firmly on the floor.  It’s also considered impolie in China to place one’s feet on a table or desk.
 

Using two hands:  When you’re presenting or receiving something, it’s important to give or receive it with two hands. For example, a business card should always be received and presented with both hands. This is a gesture of politeness.
 

Backslapping and bear hugs:  the Chinese don’t know what to make of these gestures and are just as uncomfortable with the physical contact as we are. If you want to irritate and confuse them, this will do it.
 

Winking, whistling, and clicking fingers:  this is generally considered rude in China.
 

Blowing your nose in a handkerchief: The Chinese consider blowing ones nose in a handkerchief, and returning it to one’s pocket, to be unsanitary and very American.