Be suspicious of any work that is not building product or getting customers. It's easy to get sucked into an infrastructure rewrite death spiral.

Startups are very hard no matter what you do; you may as well go after a big opportunity.

If you compromise in the first five, ten hires it might kill the company.

You have to find a small market in which you can get a monopoly and then quickly expand.

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

I think as a rough estimate, you should aim to give about 10% of the company to the first 10 employees.

In YC experience, 2 or 3 co-founders seems to be about perfect.