How much of your inventory can you bring? If you can't bring it all, maybe you can send the staff a link to your Etsy shop saying you'll bring as many items as you can, but will be sure to bring items people are especially interested in.
People will try to get deals - be sure to know if you can do this. Don't be afraid to say no. Practice saying no if you have to! People also might ask about custom orders. What is your policy about this? Have something worked out. Do you take money down? How do you accept payment? Have all of those things sorted out so you look professional, even if you don't feel like it!
Have all your payment methods sorted out before you arrive. Stick to your guns - just because you used to work with someone doesn't mean you can trust them to pay you next week! If they can't pay you cash and you can't take credit cards, maybe they can pay on Etsy.
Even if people don't buy from you that day, they might keep you in mind for future shopping needs. Bring business cards, an email sign-up list, whatever you have. Wear as many of your items as you can. And have fun!
