If an American offers you something, they will understand your “yes” to really mean “yes” and your “no” to literally mean “no”.
“Something that I noticed here was that people are very friendly and sociable. You can greet any random stranger on the street and they will respond with the same enthusiasm. People appreciate it when you hold a door open for someone, and maybe these things might go un-noticed back in India. Back home I’ve never seen anyone look at another stranger and greet them randomly.
To students who are new to the US, some people here may seem rude because of the things they say, but they don’t say such things thinking that they are rude. I had an incident where I was out with my cousin and his friends who were all Americans. I was sitting in the back of my cousin’s friend’s car, and I asked him if I should wear the seatbelt sitting in the back seat and he said “I don’t care”. What I didn’t realize at that time was that he just meant he didn’t mind if I did or I didn’t, and I thought he was being rude. Over time, I realized that that is the way they usually talk to each other and that there is nothing rude about it.” (Adi Divakar Venu, India)
“In my opinion, Americans are used to having more personal space compared to Asians. It is often said that they prefer to talk with someone about two feet away. Please don’t be disappointed when your American classmates move back from you during a conversation.” (Kyungha “Katie” Kim, South Korea)
Time Management
Time is an American value. There is an expression that says, 
“Time is money”. Americans “save” time and “spend” time like money in a bank.
Trash, Littering, and Recycling
The idea of recycling has become very popular among Americans in a collective effort to take care of the environment.
Not all Americans recycle, but local governments and organizations have made it an easy responsibility by providing recycling bins to homes, institutions, and public places.
Most Americans, even in a business setting, will prefer to be called by their first name. However, it is good principle to address them by their title (Mr., Mrs., Ms., Dr., or Professor) and last name unless you are invited to do otherwise.
“First of all, the first name is the given name, while the last name is the family name. In America, people write their first name before their last name. This is very different from the custom in Eastern countries. For example, Chinese people always write their name last name first.
The First name is used very often in American daily life. When you hang out with your friends, they will only call you by your first name. However, in many other countries, people call others by saying both the first and last name together. Here is a story that happened to one of my Chinese friends. He called his American roommate by using his given name and family name together. This made the roommate feel uncomfortable and think that this Chinese boy was rude.
Another tip is to try to say sorry and explain culture differences when you did something wrong because of misunderstanding about customs. People here are friendly and open. They will understand and forgive you after your explanation. Do not be shy!
The last names always come with titles. Of course, titles are used before the family names. You will use Prof. or Professor XXX as the title before the family to call teachers in college. Doctor or Doc may also be used for your professors based on the actual situations. Nonetheless, some professors prefer students call them by their first name. Professors will explain which way to call them is prefer during the introduction in first class. Hence, be careful to when you in the class. Another thing is about Mrs. / Mr./ Ms. You should use Mr. when you call a man. The other three are used for female. Miss is used for an unmarried female. Whereas, Mrs. should be used if the female is married. In situations which you do not know if the female is married or not, please use Ms.” (Yu “Ellie” Fu, China)