IIn order to sell, you have to look at your potential market. What it wants, what it needs, and so on. Price is always a factor as well. Basic and less expensive usually., in my experience, sells better than artsy and more expensive. Remember, Sam Walton became a multimillionaire (big money back then!) by selling stuff for 5 cents cheaper than the competition down the street.
My sales are basically simple holsters, cartridge belt slides, and similar items. I net about $1200-$1500 per month. Not great, but decent for an old retired guy.