I haven't done either cons or fairs for selling just art. I have done craft fairs and sold things like hand sewn dolls and block printed cards and jewelry and things. But, when it comes to art I dont feel like I have the skill level yet. Art,
whether a print or an original, has little practical purpose, so it can be a bit harder justifying buying it. An earring can be worn or a card written in and mailed to someone, so its easier for people to justify a purchase. Personally, I only put out money for a print or an original if I really really love the piece or have been following the artist for a while and want to support them. That may seem cheap, but we have a family and a budget. I hang art on the wall or stick it on my desk, but doesn't do anything aside from make me happy. So, when we are tight on money I don't justify "impractical" purchases at all. Anyway, Because that's how I am with money, I haven't even tried to get my own art into a fair or a con. If I get enough pieces (at a skill level that I feel matches the professionals I see) and I have a decent following online or wherever, then I might consider it. I see a lot of the artists I follow on Instagram telling their 300k followers "Im at booth number ___! Come see me this weekend if you're in this city!!' And I have no doubt they do well. But just to show up and sit among them with my 900 followers and try to, in essence, compete with their art for business. Yea, I'm not there yet. Although, I'm not sure I'll ever reach that "confident" state as an artist. It seems to be a pretty elusive feeling no matter how much I learn.
I'm interested to hear what other people's experience is though. I tend to be very self-critical, so I have a hard time putting my art out there.