and don't worry about getting a lot of display stuff. Do the ones where they supply a table.
There are people who make a living working the various craft fairs, and depending on what they're selling, they may need a full-sized van to carry the tables and display cases and so on.
I crochet and make jewelry. I have pared down what I sell to a particular style of scarf and earrings. I make some extra money, but could not possibly make a living at it. Actually, if I could sell all the earrings I make, and I only charge $5.00 a pair, I could probably make a decent living, because they're so easy and fast to make. But I can't sell them all, alas.
I actually do my best sales when I have no competition. I work an information desk, and I have an amazing amount of down time, and the company doesn't give me any other tasks to keep me busy, so during the cooler months I quietly crochet on the job. People will notice what I'm doing, admire the scarf I'm making, and ask if I sell them. Yes, I do, and do so very discreetly. I will always have at least five or six other scarves to show them. It's a slow day when I don't sell at least one scarf that way.
I have considered getting a kiosk one of these years at the local mall, but I would need a much larger inventory built up than I currently have, but perhaps some day.