Culture respect comes from culture understanding. Interpreting a new culture with existing knowledge will lead to misunderstanding and confusion. 

Culture taboos:

1. In Chinese, the number 4(四, sì) sounds like the word for death (死, sǐ). For this reason, the number four is considered unlucky and disliked by many—particularly on phone numbers, license plates, and addresses. 8 (八 bā), however, sounds like "get rich/prosperous" (发, fā) and is favored by almost everyone.
When a Chinese says “someone is a 250” , it means "someone is stupid/silly". 

2. Is Taiwan part of China?
I'd advise you to steer away from sensitive political topics such as communist party, Taiwan's independence, Tibet or Uighur problems unless you know very well the person you are speaking to. Bringing those topics up will likely offend most Chinese and start you off on the wrong foot. When you are familiar with your friend's political stance, you'll be more ready to broach the subject. 
 
3. Chopsticks should not be left standing straight up in a bowl of rice. This act is said to bring bad luck as chopsticks stuck in rice look similar to food sacrificed/served to the dead, which is reminiscent of a ritual for paying respects to a dead person at his/her tomb.

4. Although red is the color of celebration in Chinese culture, such as wedding and holiday celebration, red is  not the best color to write a person's name in. A Chinese legend story says that the God who rules people's death writes down the names of the dead with a brush pen in the color of red. White is used in funerals to signify someone's passing, as in a lot of other Asian cultures.

5. Ask your host if you should take off your shoes when entering their home. Some Chinese family would prefer you taking off your shoes and changing into slippers they provide upon entering their homes. Not every family has a "no shoe" policy so it's always a good idea to be observant and ask when entering.