Here are a few things I learned at my 1st outdoor show (2nd show overall). Ypsifest in Ypsilanti, MI.
1) If you're going to pay extra for electricity make sure the event can actually provide it.
I paid $50 extra to have electricity to run my fan, laptop and a couple lights. I get to the location and they had me plug into another vendor's generator. I think next year I'll just split the cost of gas with the other vendor.
2) Know your audience's pricing expectations. My first day I made $4.50. Second day I lowered my prices and brought in over $300 with only slightly more traffic coming through. I still made a profit.
There was a spray paint artist across the way that I spoke with regularly throughout the weekend. He was selling piece that he painted on site for $20. On the first day I commented that he should be charging at least $30. He told me that he'd tried that before at similar shows and his sale plummeted. Apparently $20 is the sweet spot for that kind of event. I couldn't really argue, because he was selling pieces non-stop all weekend. I don't think he even stopped to eat on Saturday. He said he can charge $50 at bigger events like Art Prize in Grand Rapids and people won't blink an eye at that and he'll be selling stuff faster than he can paint it for 3 weeks straight.
3) I really need a van. Transporting everything stuffed into 2 cars is annoying.