One thing to really internalize is that a business is not a product. If you just look at some product that's gotten investment and think "why would they invest

One thing to really internalize is that a business is not a product. If you just look at some product that's gotten investment and think "why would they invest in that?", you're thinking about it wrong. The entrepreneur that's been out raising that round has been out pitching a vision for a large billion dollar business, with that product as just one of the initial steps on the road to getting there. To raise money from investors, you'll need to on the one hand present a vision for a large business like that, a clear road-map to getting there and sufficient proof to convince them that you and your co-founders are capable of executing on that vision and that road map. Sometimes you prove this with a working product and traction around it, sometimes you can prove it because of a stellar background (having done it before) and sometimes you prove it because you're pitching to people who already know you very well and believe in you.