I agree with visiting craft fairs to see what they are like before signing up for them. I have had a couple that went bust, but I have also had some where I did quite well. I have found that I did better a juried shows that are exclusively handmade. Sometimes it is harder to compete at shows that include re-sell items in the mix. I prefer indoor shows as I don't tolerate the heat very well, but will do outdoor shows in May and June, Sep, and October.
If doing outdoor shows, make sure you have a good tent for shade and protection. Here is a link to my blog I did a couple years ago about preparing for outdoor shows. Just scroll down to the Aug 26 entry.
http://whittywirejewelry.blogspot.com