With new and untested ideas, there’s always some risk involved, but everyone has a different level of risk tolerance.
If you’re less risk tolerant, then I would put more effort into market research, so you do a better job of aiming where the demand is. That way you don’t waste your time creating something that no one wants to buy.
If you’re more risk tolerant, you can take the chance of doing something new where it’s hard to conduct market research. Success is far from guaranteed, but you might just stumble upon some previously unknown demand.
This is a matter of personal choice, and your preferences may change depending on what else is going on in your life. It’s like any form of investing. Do you want to play it safe and deal with relatively predictable outcomes, or do you want to take a chance and explore uncharted territory?
That said, if you’re more of a risk taker, you can bypass all this and go with whatever inspires you. You might hit upon something new that works, but you could just as easily end up with a total dud. Who would ever want to do that? I sometimes like doing that. It can be exciting to try something new and see what happens, assuming you can handle it if it doesn’t work out so well. This is especially doable for small projects where the downside isn’t so terrible if it doesn’t perform.
Since I have enough streams of passive income to support me, I can afford to take more chances with new income streams. But if I was just starting out, I might be more conservative and make sure I’m tackling projects where I can predict strong demand.
A lot of this research can be done with free tools and public information. For example, you can see how well any book is selling relative to any other book by checking the sales rankings on Amazon.com. For all kinds of products now, you can get a decent idea of how well any particular product is selling just by looking at public data.
This is not difficult if you have decent Internet skills.