Just be friendly, approachable and open to learning. I live with the theory that if I listen to what people say, even though I might already know it, the worst that will happen is it refreshes my memory and I might pick up something new.
I'm on a first name basis with the people in my local tack shop, and that's what keeps me going back. A friendly person who you can chat to is what brings you back.
Hope this helps a bit :)