I have done more a few shows now and the most important thing is to have a second person there with you as said by others. You need them to have basic knowledge of what you are doing but the main thing is that they will be able to keep an eye on your kit, sell your stuff and stop any one from entering your work area. make sure you rope off a big area to work in ( I always ask the organisers for at least 8m x 8m you will be amazed how much space you can fill. take a gazebo or other shelter for the person helping you to stand under and to keep your kit dry but have it within your roped off are so that people cant wonder into it.
stuff your helper needs to know.
Most important. where is the first aid post and event organiser in case any thing goes badly wrong.
How to get your attention without putting them self at risk of you turning round and slashing them up.
what kind of wood your using, people always ask.
The Price of every thing.
what you are carving on the day.
do they need to treat their carving that they have just bought and if so what with.
make sure you have business cards or your contact details displayed.
have a photo album of your portfolio.
I always have my piece im planning to work on roughed out so that when people start coming round there is something for them to see right from the start. you may think you have all day to carve but the truth is every time you stop to refuel there will be some one waiting to talk to you and the hours will race by. my general rule is for an 8 hour event I will look to carve something I know I can finish in 3hrs tops . make sure it is some thing that doesn't need sanding and lots of finishing off, so that if some one wants to buy it when you have finished it they can take it home with them on the day. I take a few spare logs just in case I need to bulk out my time and carve some small stuff.
remember to take stuff for cleaning up after yourself.
remember to take your PL insurance certificate with you as some organisers will not let you set up until they have seen it.
have fun