I would second validating the idea. This also ties in closely with talking to users/customers.
There is a nuance to validating that I have tripped on. You want to find a way to validate that customers will buy. That may be a difficult test to setup, but where I’ve stumbled is getting positive feedback and confusing that for validation.
A lot of times when people express interest, you may be hitting on something, however they may simply be validating the idea is interesting.
Unfortunately there is a big space between something people are intrigued by and what they will actually pay for.
Another question I wish I’d thought more about is: Can I set up something basic to get traction while I build? Whether it’s leveraging Typeform or Notion or some other tool. Is there a simple thing you can offer the customer base to serve them while you work on the first version of your product.