Wow, that flea market is HUGE! 600+ vendors is crazy. The booth fee is pretty low and if they supply the tables that's one less thing for you to have to haul. Do you need to have a canopy or is there shade....or are you not a pale person like me?
Funny that you mention American Girl clothes. A friend of a friend makes them as well. Is that a popular thing now? Since I don't have kids, I have no idea.
With this sort of business, it's all trial and error. You'll learn what sells and what doesn't and which displays work and which just don't. Every time I do a show, I learn something and, for a few years, what I learned was what NOT to do BTW - I scoured Pinterest for display ideas. I didn't copy anyone, but I got little ideas here and there.
The trick is to not take it personally if things don't sell right away. Just have faith in your work and your ability and know that your customers will find you. If I have a piece that I am sure will sell and it just doesn't, I tell myself that the person who will buy that just hasn't seen it yet. If people go to a neighboring booth and spend money there instead of with me, I just say, "those aren't my customers." It's hard to not take those things personally, because these are things you created. I pay attention to what people buy and don't buy and adjust accordingly, but I stay confident in my abilities.
I know lots of artisans who just hate doing shows and find other ways to sell their work. Aside from the hauling things around aspect of it, I love shows. I think people are interesting and I love meeting customers or even having a great conversation with someone who doesn't spend a dime with me. When I was first starting out, a very experienced seller gave me some advice: You're not only selling your work; you're selling yourself. YOU are the product. If they like you, they'll stay in your booth and the longer they're there, the more likely they are to spend money. I tend to be a little shy (I know - shocking) and have a bit of social anxiety, so this business has actually helped me get over that a bit.
Oh, and I HIGHLY recommend getting a Square or other credit card payment system. I can't imagine doing craft shows without one. If you sign up on the Square website they'll mail you the Square for free. I bought one for $10 at an AT&T store and when I linked my bank account to my Square account they deposited $10. No monthly fees and just a small (firstname.lastname@example.org%) transaction fee and the money is in your account in a day or two.
Okay, enough with me hijacking the thread. If you have ANY questions, just PM me