I've done a few in my time, with various types of product. I've never made any kind of real money at them, find them demoralising and a huge waste of time, effort and money.
Just for a bit of context, I once spent £70 renting space in a 3-day fair, pre-Xmas, in a very posh venue. I'd spent hours and hours making lovely candles in hampers, organic, soy yadda yadda. I sat and watched for 3 days as every single person in there walked past me and the woman across the way with a machine for embroidering dogs onto towels made an absolute fortune.
My friend is now setting up a business, both online and at fairs, with a view to opening a real bricks and mortar shop in the near future. I've given her some of my pieces as stock, sale or return, so have a little bit of a stake in her success. She's having the same kind of experience as I had at fairs and I'm struggling not to colour her experience with my attitude (which is, basically, sack them off).
So has anyone ever had a fab time selling at a craft fair or similar? Made heaps of cash, networked like a good 'un, handed out a rainforest's worth of business cards and gained hordes of Instagram followers? I mean, someone must do, right? Otherwise why would anyone bother? And if so, what's your secret(s)?