You can create value with breakthrough innovation, incremental refinement, or complex coordination. Great companies often do two of these. The very best companies do all three.

By the way, that's my number one piece of advice if you're going to join a startup: pick a rocket ship.

The most common post YC failure case for the companies we fund, is they're incredibly focussed during YC on their company... and after they start doing a lot of other things. They advise companies, they go to conferences, whatever.

The startups that do well are the ones that are working all the time.

If you have several ideas that all seem pretty good, work on the one that you think about, when you're not trying to think about work.

Before product/market fit, your only job that matters is to build a great product.

One of the keys to focus, and why I said cofounders that aren't friends really struggle, is that you can't be focused without good communication.