If someone is being mean to you still be nice to them. Don't bring yourself down to their level by being mean back at them. They might get your drift and stop being mean to you, talk to them nicely so they don't take it a wrong way.
Try to compliment people
Do not compliment on a daily basis to the same people or else they will think you are trying to "butter them up" before asking for a favor. Only compliment if you truly mean it.
Remember using vulgar language won't make a very good impression
Always remember the Golden Rule: Treat others the way you want to be treated. And respect them for who they are. don't change them. Even though some people may not be nice to you at first, they will come around eventually.
Don't laugh at other peoples' mistakes and don't point out their faults too harshly. It's okay to joke, of course, but use your common sense; think about what you're about to say, and consider the fact that just because you may not be offended by a certain comment, others could be.
Bad language, gossiping, whining, selfishness and greediness don't mix with being nice.
Source is Internet.