You want an idea that turns into a monopoly. But you can't get a monopoly, in a big market right away; too much competition for that.

AirBnB spent 5 months interviewing their first employee, before they hired someone and in their first year, they only hired 2 people.

In general, it's best if you're building something that you yourself need.

In YC's case, the number one cause of early death for startups is cofounder blowups.

In the early stage of a startup, hiring senior people is usually a mistake. You just want people that get stuff done.

Losing focus is another way that founders get off track.

... for the top twenty most valuable YC companies, all of them have at least two founders.