All great tips! I used to do craft shows with my MIL many years ago. It was a fund-raiser event at her church and she always picked up the tab for the $20.00 table rental space. I didn't do quilting way back then. Most places where we live now charge a lot of money to rent a booth, and I'm getting too old for that stuff now.
In addition to all of the above tips which are great, here are a few of my own.
Have several in expensive items that will help to draw customers to your table. If you've got lots of scraps, you could make several pocket tissue holders to have in a basket. Here's the tutorial that I used.
http://www.quiltingboard.com/tutoria...r-t107636.html
You can easily make 30-40 of them in an evening if you chain piece them. I work at three different schools each week and made about 40 of these for each of the ladies I work with as a small Christmas gift. You could sell them for $1.00 by themselves, or $2.00 with a package of tissues in them already. They are so easy to make and look adorable.
If you plan on selling any bigger ticket items, you may want to set up an account at
https://squareup.com/?sro=1. If you set up an account online, they will send you a free square reader to use with your tablet or smart phone to accept credit cards. You can also get these at places like Best Buy, but you will have to pay $9.99 there. They charge a small processing fee only when you use it. If I was selling a $300.00 quilt, I would much rather pay a 3% fee and know that I don't have to worry about a customer's check bouncing on me. The customer uses their finger to sign for the charge on your touch screen. My daughter has one and it's worked out great for her. You just download their free app to your phone or table to use the device. Many folks carry only a limited amount of cash and may be willing to spend more money if they can use a credit card.
If you are going to use one of these credit card adaptors or would simply like to have access to an electrical outlet to add lights to your table or whatever, you may want to ask if you will have access to an outlet or if there's a charge for it. Be sure to bring one or two heavy duty extension cords and a power strip if you think you will want/need electricity. It also comes in handy for charging your cell phone during a long day.
Depending on how many things you can reasonably put on display at one time, you may want to consider taking pictures of each of the quilts or larger items you're selling and put them into a photo album or sheet protectors in a 3-ring binder. If your information includes prices, dimensions, etc, your customers can look through the binder to see if you have any other items they would like to take a closer look at.
Consider offering bundle prices such as choose one free hot pad with every table runner purchased. Get 3 free tissue holders with each baby quilt. Buy two table runners and save $5.00 off your total purchase. I think you get the picture.
If you have a very comfy lawn chair, you may want to bring it instead of using one of those uncomfortable metal folding chairs that are usually provided. If I have to sit in the same chair for 8 to 12 hours a day, it needs to be a comfortable chair.
A folding snack table always comes in handy to have next to your chair.
I hope you have a very successful sale!