I have always found my mentors at the flying field. I find the ones that are actually flying every time I show up, friendly, and helpful. There are always a few at each club that I can count on to be there rain or shine, always willing to give a hand, and always welcoming to new people.
There is another group I see that show up at the field, set up in their own little corner, and refuse to talk to anyone. They will let a visitor stand there and completely ignore them. Sometimes they are willing to talk, but only to tell you what you are doing wrong or to criticize. I have seen more newcomers driven away by these types than any other. We have all seen them and probably have a few of them at our clubs.
I try to be in the first group, helping others out like I was helped when I first started.