Others have said build a better mousetrap, but that isn't your problem. You just need to solve somebodies problem. It could even be yours. The one that stood

Others have said build a better mousetrap, but that isn't your problem. You just need to solve somebodies problem. It could even be yours. The one that stood out to me was identifying which pet is at your door. It sounds like that was a problem (probably pretty minor...?) that you wanted to solve yourself. Show people how you solved it, and others might comment on it and say, "That's really cool! Can you make me one?", or offer some new feature idea that would make them say it's really cool. Boom! First customer. Hell, don't even tell them you made it, see if they ask you where you got it! Basically find a need or want from somebody else for something you find fun. People like cool things. An example of something to probably not do again would be the Boulder tubing thing. Was it a problem you or others had? The flow rate can be visualized by looking at Boulder creek, which runs through much of Boulder, and by going outside... which it's almost always nice anyway ;) So I don't see how it would solve any problem you had even.