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

A board member of mine used to say sales fix everything in a startup, and that is really true.

You have to be decisive. Indecisiveness is a startup killer.

It's better to have a few users love your product than for a lot of users to sort of like it.

The role of the board is advice and consent. If the CEO does not lay out a clear strategy and tries to get the board to set one, it will usually end in disaster.

Even though plans themselves are worthless, the exercise of planning is very valuable and totally missing in most startups today.

Stay focused and don't try to do too many things at once. Care about execution quality.