Sam Altman says successful startups figure out a clear, important mission within one to two years. Start by solving your own problem, then become an evangelist for that mission to attract people and build passionate users.
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You don't have to figure this out on day one but all of the most successful startups I've been fortunate enough to be a part of pretty quickly, first year, two years at the outside, they figure out a really important mission and it is this mission that gets people to join them, that drives them, that drives the founders, that gets the media to write about them. And even if you start off building a project that's just interesting to you and solves the problem in your own life, which is how you should start, remember to at some point have a clear mission, you have to become a great evangelist for this mission. One other skill that didn't make it into this version of the deck is is being a great communicator. But you need to clearly think, clearly communicate this clear mission and that is what will convince people to come help you and that is how you will build this idea into this huge company and all these people that really love your product.