1. be professional, take other people seriously, but don't take yourself too seriously.
2. be good and helpful to other people, it will come back to help you.
3. make other people's job easy, be considerate to your boss and other people when make presentations, but don't shy away from tasks. Always thank people for helping you.
4. if you feel wronged, tell your boss you will take care of it anyway.
I believe if my mentors think these are important advices to give me, they must have run into situations that need these advices. So not all situations are discrimination. Everybody ran into difficulties. For particular difficult collegues, everybody knows his reputation. One strategy is to let people know that that person has done wrong to you, creating a good reputation for yourself.