Nodding is used to greet somebody.
Keep gestures and unusual facial expressions to a minimum. Chinese do not use their hands when speaking, and are annoyed by people who do.
Avoid touching, as Chinese people dislike being touched by strangers.
Always acknowledge the most senior member in a group first.
There is not an emphasis on emotions in China, so be careful on how often you use them.
Do not spit. Spitting is unacceptable and a fineable offense.