Talking to clients - I'm learning about that, too. I feel much more comfortable selling myself and my work, now. However, there were a few times I think I could have closed the deal, but I let the client walk away.
Talking to the juror - The juror was very nice and professional. She only spent a few moments in my booth and asked me to describe my work (in a sentence or two). Next time I'll have my "elevator speech" ready! I don't think I did a terrible job but I can do much better and it may make the difference in winning an award (I didn't).
I'm looking forward to the next art festival! What have you learned?