I signed up for my first craft fairs last winter. Both were in the basement of a comedy club in Brighton. The first one went pretty well, but I soon realised what kind of price people expect to pay at these craft fairs. Once I lowered my prices, coasters began to sell quickly. As long I am still making a profit, it is more important to me for new people to see and buy my art.
I did another fair 2 weeks later, and this time brought along cheaper things like super tiny prints which I sold for £1.00 each. These sold out within the first 2 hours. I also did some mug and coaster sets winch all sold out and had a few people who kept coming back for more.