Many ask how do you know if a craft show is right for you. The only way to really find out is to visit the show before you apply to do it the next time it is run - which is usually the next year. By attending the show, walking through with the eye of a buyer and the eye of a potential seller, and taking notice of -
How many visitors are at the show?
How many craft booths are at the show?
Are visitors actually buying or just looking? - you can tell by what they are carrying.
Would your crafts fit into the show?
Are there already many booths selling the same type of things that you will sell?
Who are the visitors at the show? Children? Families? Rich? Couples? etc.
How many "craft" booths are selling commercial, non-handmade items? (Don't be surprised to find many!)
Observe everything that you can. Take notes. Before or after the show contact the promoter or location that hosted the show and find out how much the entrance fee is and get on the mailing list to get an application for the next show.
Sometimes there are several shows run by the same promoter - these shows tend to usually be the same at various locations. By visiting one you can get a good idea of what others will be like run by that promoter. You can visit one and apply for the next which may be just a few months away rather than having to wait a year for the Town Craft Fair to be run again.
This is really the best way to find out. But it is not fool-proof. Some shows will change year to year. What may have been a great show this year, may be a show full of commercial merchandise the next year. But, with show costs as they are - visit the show first!