Dinner is a normal social situation, there are also some important TABLE manners（餐桌礼仪cān zhuō lǐ yí ） you need to know while you are enjoying the food you like.
The fact that different cultures have different manners really makes this lesson hard to go on, so I will just list the most important table manners in the western world and Chinese.
Don't get you hand on chopsticks（筷子 kuài zi ） before the important guest or elderly does.
During the first toast, sip a little from your glass after the host says “Please”.
Take food from plate in front of you.
Use common spoon to get soup.
Use both of your hands to hand over tea or wine.
Don’t point spout of teapot to guests.
Keep your voice down during the meal.
Don’t talk with food in mouth.
Put plate on the table.
Napkin on knees; Napkin in the chair if you left for a while; Napkin on the table if you finished the meal.
Cross the knife and fork to show you are not done with the meal; Put the knife side by side on plate to show you have finished the meal.
These manners are for formal social situation.
If you are invited to a buffet or potluck, you can be more casual.