Step #2: Talk to these different sets of people. Ask them about the problem first, not the idea — do this at least 500 times.
Raad hits directly here on the on main fault in the Lean Startup Methodology — — not spending enough time researching the problem and directly inter interfacing with end users about it.
The idea needs to solve a problem that’s big enough in its respective vertical to solve a real problem. You need to go past “good enough” For example — if an Excel spreadsheet is “good enough” for a person to do his or her job, what’s the catalyst to make them want to jump to you “new and improved” software. Your product needs to have demonstrable results.
Stick with a problem to solve in your own vertical. You already have the necessary expertise as a thought leader which is critical with both end users and investors.
Do the user interviews — yes, I know it takes time and delays the process — but it will save you a ton of time and more importantly money going forward