I listed the widget I made on Tindie and then promptly forgot about it for a few months. But when I got some initial purchase orders, I started paying attention again. When I got a repeat order from a customer, it had my complete attention. I called that customer, we talked about exactly what problem it was solving for them, and I learned a lot. However, it still took me another two to three years before I stopped everything else I was working on to focus on the widget full time. But now that widget has been my main focus (and source of income) for the past seven years.
Edit: One thing that helps is if your widget is a good-enough replacement or alternative for something that people are already buying for 10x the price of your widget. Even if your widget kinda sucks (it will! it does!), people will be so happy that they're saving 10x of their $$$ that they won't mind your widget's flaws... and they'll enthusiastically tell you which flaws matter and which ones don't, so you know how to improve it in the future.
tl;dr: 1) Pick a widget category where you can make a thing 10x cheaper than the competition. 2) Get a customer. 3) Talk to them. 4) Take notes.
Pretty easy to create an account and make a new listing. My widgets are used as test equipment. There is a specific FCC certification exemption for testing tools. 47 CFR § 15.103 (c)
Edit: One thing that helps is if your widget is a good-enough replacement or alternative for something that people are already buying for 10x the price of your widget. Even if your widget kinda sucks (it will! it does!), people will be so happy that they're saving 10x of their $$$ that they won't mind your widget's flaws... and they'll enthusiastically tell you which flaws matter and which ones don't, so you know how to improve it in the future.
tl;dr: 1) Pick a widget category where you can make a thing 10x cheaper than the competition. 2) Get a customer. 3) Talk to them. 4) Take notes.