In YC's case, the number one cause of early death for startups is cofounder blowups.
A lot of people treat choosing their cofounder with even less importance than they put on hiring. Don't do this.
One of the top causes of startup death - right after cofounder problems - is building something no one wants.
Cofounder relationships are among the most important in the entire company.
Finding a technical cofounder would have been difficult for me. I was an English major and didn't know any computer programmers.
If you're not in college and you don't know a cofounder, the next best thing I think is to go work at an interesting company.
It's better to have no cofounder than to have a bad cofounder, but it's still bad to be a solo founder.
In addition to relentlessly resourceful, you want a tough and a calm cofounder.