Dont arrive into the USA with pre-conceived ideas of what the people are like. Be courteous and polite with Americans and you will see they are the friendliest and most generous people you could wish to meet.

Forget what you may have seen on TV or in the cinema -- this is rarely a window on reality.  If American movies were to be believed, all conflicts would be resolved with guns, all women would wear stiletto heels and would go to bed with the hero by the middle of the film, all police would be mercenaries with a deathwish, and most people would care only for wild parties and Prada handbags.

 The truth, however, is by far less dramatic.  Most Americans, for example, do not know how to fire a gun unless they have served in the military and those that do own them use them for nonviolent purposes, like hunting wild turkey.  Policemen carry guns in case of violent criminals and the typical procedure is to use lethal force only when someone's life is threatened as dictated by law. (the aim is to disable a perpetrator first, not kill him, and police who abuse this power face being sent to prison for life.)  American women have lives that are much quieter (and with less wallet space) than the women of S*x and the City: their top priorities are far less about the new line of Jimmy Choo's and far more about juggling their careers with their personal needs, like paying rent.  And though there are plenty of glamourous parties and charity balls in New York or Hollywood, the average American isn't there: parties for the average citizen are much smaller, more intimate, and much less grand affairs, usually with just family and friends on the guest list, and debate about what is going on in the news is actually just as likely to be heard as anything about a celebrity's recent escapade around the table. 

Make your own choices about people and you will soon make lots of new friends. Americans might have a few misconceptions about foreigners-tell them how you do things . Many people you meet may not have been out of the U.S. at all,  due to lack of money and vacation time (the average American is only allowed two weeks per year, and taking days off for holidays may be deducted from this total.) Also, the sheer size and variety of travel and culture available within their own country makes domestic travel much more popular and affordable for most Americans.  However, they usually love talking to foreign tourists and will be delighted to learn about other cultures. Take care what tone you use when comparing your home country to theirs, however, as some may take this as criticism or snobbishness.