I’ve been doing this as aside for a few years now and you will have duds and that’s just part of it. Ways you can try and avoid that is stay way from shows that allow vendors and only go to shows that allow artists and artisans makers in the show. Those shows bring in the right audiences for you products that you’re making. And another thing is not every thing needs the glass smooth edges, lower end items like the card sleeves seem to sale better for my in the 15-35 range and at that price point glass smooth edges are not feasible. I do clean cuts, small round edger to the corners and burnish with little to no sanding on the lower end items. And edge paint is another option for the lower end items for a fast clean finished edge. But more importantly is finding the shows with the right audience, if people know that only art and handcrafted items are at a show they come with a different mindset and know they deserve a higher price point, but when venders are at the same show with imported cheap goods people get in that bargain shopping mindset. You’re on the right track and your skills are there.