The other piece besides focus for execution is intensity. Startups only work at a fairly intense level.

In general though, if you look at the track record of pivots, they don't become big companies.

A lot of people treat choosing their cofounder with even less importance than they put on hiring. Don't do this.

You need conviction in your own beliefs, and the willingness to ignore others naysaying.

More important than starting any startup, is getting to know a lot of potential co-founders.

I believe in fighting with investors to reduce the amount of equity they get and then being as generous as you possibly can with employees.

It's difficult to get large groups of people, to the extreme levels of focus and productivity that you need, for a startup to be successful.