Americans prefer to have some personal space. Standing very close to people, touching them, or rubbing against them when it is not strictly necessary is very rude and may be considered hostile.
Americans look each other in the eyes when speaking, and failing to so so may make them suspicious of your intent or meaning. They may think you are very shy and go great lengths to make you feel comfortable when not necessary.
Americans shake hands when meeting new people and upon the finish of important business transactions or leaving the home of a stranger. It is not necessary to shake hands, bow or otherwise physically demonstrate your understanding or thanks in day-to-day or informal life.
If you wish to acknowledge another person without speaking to them, a small nod of the head is appropriate. This is useful if you meet the eyes of a stranger by accident and do not want them to think you are rude.
Americans use “please” and 'thank you" with each other and serving staff in restaurants.
It is more polite to use these than to forgo them if you are uncertain.
Americans do not directly discuss politics, income, religion, or personal sexual information with strangers. While many will happily discuss such matters with you, it is polite to wait until you have made small talk to discuss these topics. Additionally, once brought up, Americans can be very frank and aggressive about their positions on these subjects. Many are poorly informed and do not understand political terms in the manner you may. It is better to avoid these topics.
Americans will ask you where you come from, your background, or about your accent or language. Nearly all of these questions are curious and friendly. It is good manners to answer them. Many Americans are very curious about life in other countries and cultures. Discussing this is a very good way to make friends.
Many Americans wear shoes in the home. If your host has shoes by the door, or asks you to remove them please do so. If not, it is usually the custom to keep them on unless the host indicates otherwise. If you are uncertain it is polite to inquire as Americans want most for you to be comfortable in the home.
Americans keep many types of animals as pets. Dogs and cats are most common, but rabbits, mice, and other small animals are often kept, as are birds. Most consider the animals to be part of the family and may allow them to sit on the furniture, free reign of the home, or cuddle with them. It is rude to comment on this if you disapprove of it. If a pet animal is making you uncomfortable, it is polite to ask your host to correct the issue. Never beat or kick an animal in the home of an American.
Americans value cleanliness and most bathe every day. They use deodorant, brush their teeth or use mouthwash, and comb their hair daily. Being clean is part of being polite in American society.