Make a landing page, Try and get emails, gauge interest vs. how much risk you are willing to take and go. I'm doing this right now which is interesting because

Make a landing page, Try and get emails, gauge interest vs. how much risk you are willing to take and go. I'm doing this right now which is interesting because every other time I tried it was "build and they will come". Marketing is definitely the harder part. Capture attention with your idea and then implement.