Do not forget to silence your phone and do not talk on the phone when you are in any kind of audience; at the opera, theatre, cinema, places of worship, or lectures/classes. While texting is also rude in these circumstances, younger people are more likely to think nothing of texting wherever they please, but that does not mean that it is accepted. Having your phone make noise or light up in a dark environment will inconvenience people, even though they may not immediately say something.
Greeting People: Most Americans, even in a business setting, prefer to be called by their first name. However, it is a good rule of thumb to address them by their title (Mr., Mrs., Ms., Dr. or Professor) and last name (i.e. Mr. Anderson) until you are specifically told otherwise. Americans may also address you by your first name immediately after being introduced to you. This is not considered rude at all and reflects the more casual style of Americans.
In the military, a man of higher rank is addressed as "sir" and a woman of higher rank is addressed as “ma'am.” However, it is not uncommon to hear sales people interact with their customers using these expressions of courtesy. In some households children are still taught to always address adults by including "sir" or "ma'am". The word "Lady..." is never used to gain the attention of a woman or address her directly. "Miss" or "Ma'am" is correct.
Staring: It is a good rule of thumb while out in public not to stare at others.
Passage: Americans walk to the right on sidewalks. It is polite to move over to the right, especially if you are a group of people, when only one person is walking toward you to allow room for them to pass.
Shopping: When shopping, it is not acceptable to get very close to another shopper in an attempt to make him move away from a product you also want to see. You must wait until that person has left the area in front of the product or you may say, "pardon me" and quickly reach for the item and then move aside.
When waiting to pay for your merchandise, you must get in line. Cutting ahead of others in line or trying to get the cashier's attention for more than a moment can infuriate people in line and may result in you being told to wait your turn. It is also never acceptable to go behind the counter where the clerk stands.
Public Transportation Courtesy:
Boarding: It is typical policy for most buses to board from the front door. Do not board the bus until all passengers exit first. On subway cars, it is basic courtesy for boarding passengers to line-up on the sides of subway train doors and permit exiting passengers to exit before waiting passengers board.
Exiting: Passengers on a bus signal the driver that they want to exit by pulling on the cord near the window or a designated button located on poles on the bus. The "bell" should be rung at least one half of a block prior to the desired bus stop to permit the bus driver to make a smooth stop at the designated bus stop.
Cellular Telephones and Music: Passengers should limit usage of a cellular telephone or force the call to their voicemail account to avoid angering other passengers. Earphones are required for all music devices.
Passenger Contact: Passengers are typically uncomfortable having conversations with other passengers that they do not know. They typically will be initially wary of somebody they do not know but will let their guard down once it is clear that the person trying to converse with them has good intentions.
If somebody is wearing earphones or is reading, it usually is a signal they would like some privacy and do not want to have a conversation.