I am studying somewhere where the faculty in my department don't like each other ---- most do not like my advisor and I have to take classes with the ones who don't like him. I'm afraid they are not going to grade me well because of this. What do I do?

i think professional jealousy is much more prevalent in academia than you imagine....some v famous reseacher once said "in academia we can afford to be so petty because there is so little at stake"

anyway the point is do not worry too much about it, be focused on your job and try to stay as much away from this politics as possible