From the Official Website of Guangzhou Municipality:
Traditionally speaking, there are many taboos at Chinese tables, but these days not many people pay attention to them. However, there are a few things to keep in mind, especially if you are a guest at a private home.
1. Don't stick your chopsticks upright in the rice bowl. Instead, lay them on your dish. The reason for this is that when somebody dies, the shrine to them contains a bowl of sand or rice with two sticks of incense stuck upright in it. So if you stick your chopsticks in the rice bowl, it looks like this shrine and is equivalent to wishing death upon person at the table!
2. Make sure the spout of the teapot is not facing anyone. It is impolite to set the teapot down where the spout is facing towards somebody. The spout should always be directed to where nobody is sitting, usually just outward from the table.
3. Don't tap on your bowl with your chopsticks. Beggars tap on their bowls, so this is not polite. Also, in a restaurant, if the food is coming too slow people will tap their bowls. If you are in someone's home, it is like insulting the cook.
