Founders of these companies react as if they feel physical pain when something isn't quite right with the product or a user has a bad customer support experience. They believe in launching early and iterating, but they generally won't release something crappy.

Make something a small number of users really love. Successful startups nearly always start with an initial core of super happy users that become very dependent on their product, and then expand from there. The strategy of something that starts with something a huge number of people sort of like empirically does not work as well.

They can explain the vision for the company in a few clear words. This is most striking in contrast to companies that require multiple complicated sentences to explain, which never seem to do really well.

Companies that fail to keep expenses low often justify it by saying 'we're thinking really big.' Successful founders stay frugal early; even after things work, they ramp spending only where it matters.

On frugality vs. the 'thinking big' excuse.

Mediocre founders try to hire people for the parts they don't like. Great founders just do whatever they think is in the best interest of the company, even if they're not 'passionate' about that part of the business.

On any given day there are 100 reasonable things you could work on. Successful founders are relentless about hitting their top two or three priorities each day and ignoring everything else—including the seemingly-important fire at #7 and the networking event at #95.

They don't get excited about pretending to run a startup. They're willing to work on things that seem trivial—like a website that lets you stay on an air mattress in someone's house. If you're more into appearance than substance, you won't want people laughing at you.

Great founders never disappear for a year and jump from nothing to a huge completed project. Even on big projects, they ship small chunks incrementally with demonstrable progress, and if they say they'll do something, it happens.