As a mentor I'd like to stress patience and attitude. How you come across will in turn affect the kind of response you get. You really have to want to be a mentor and have a want for people to become better players/more informed.

Another thing I'd like to stress is the fact that while mentors should be held to a higher standard, we're not perfect. There's times where I could not recall mechanics or exact name of skills to a fight because of not having done a fight in six months and I would say as much and be honest about it. Usually other players try to help explain or we all wing it and learn/remember on the fly. I think it's important to be humble in a place of leadership.

Third, not everyone is going to listen to your advice. If they have words, like someone else said, chalk up your losses and move on.