Some standard rules of etiquette to follow include remembering to RSVP, waiting for everyone to be seated at a table before beginning to eat and keeping all things except for food off the table. Other rules include keeping elbows off of the table and wiping with a napkin.
Although etiquette is often called "table manners," it is actually a code of behavior that delineates what is considered appropriate for a person of a particular social class. Therefore, etiquette is related to the stratification of society. As social class systems become less rigid or break down, the rules for what is considered appropriate in a particular class relax. The etiquette of 19th and 20th century America held that it was rude for a man to wear his hat indoors because people though of taking off a hat as a sign of respect. Accordingly, people who did not do so were considered socially deviant and were said to have "bad breeding."
Etiquette varies significantly across different cultures. For example, in American culture it is considered rude to look someone in the eyes for more than a second. However, in India, this is a very common behavior and is simply a sign of curiosity.