Heres a few tips I have learned
There are many factors for a good show and asking others should not be a big one.I only trust that type of feedback from my fellow professional potters whom I've known for decades and even with that my stuff sells different than their stuff.
As mentioned if its a hobby a few hundred bucks beyond expenses is not ok for a full timer but mnay be fine for someone.
If I'm driving say 1200 miles one way I need to make some serious $$ to make it work
A few key elements are the size of the crowd (the more the merrier with a few exceptions)I always do well in well attended shows
some shows like the Half Moon Bay Pumpkin Festival drwas over 300K but its a cheap crowd-meaning big stuff does not sell well.
Its takes lots of street time to dial all this in.
Exceptions are the crowd is there for another event say a music festival(not good for selling anything large) or car race or -----fill in the -- blanks
Thats not to say you cannot sell 3-6 k at such an event it just takes a lot of small sales.
I like the shows that are in towns that happen once a year and its a big event say an annual art show-It can be twice a year as well
The locals come out as well as tourists and out of towners
In areas that have shows every weekend then all the sales are diluted-the San Francisco Bay area is just such a place. Back in the 70's and early 80's-it had a few great shows
Now there is a show everyweekend in some nearby town and the public thinks oh we can go in a week or two as their is always a show close by and you will be there.
They will ask you if you are in such and such next weekend?
I always say I live on another planet that is far away and only come once a year
You need to be aware of what else happens in your show area the whole year around as to art shows.
I tend to do large annual events-they are always better than an every week event in sales.
If you are a hobbist then weekly markets will be fine but I want more sales than they can provide.(our local famers market is only for food anyway)
Good luck with the selections