Learn from others
Learning and applying what you learn is necessary to differentiate from others. Most of what you learn comes from doing, which is basically what you do in your start-up every day. No one can teach you what it is like.
However, there are some books that are really helpful, especially for early-stage entrepreneurs, and Founders at Work by Jessica Livingston is one of those. Through a series of interviews with successful start-up founders, it makes you feel how things were like when they started, how things evolved for them, and this is savvy advice. One of the things I like the most is that founders explain their errors as well. I wish I had read it several years ago!
If I should mention the three main characteristics of the founders up to the one I’ve read, I would say perseverance, love for what they do, and extreme hard work. And even with them, I guess there are many founders who fail, but without them, you would only be lucky.