The most impressive people I know have strong beliefs about the world, which is rare in the general population. If you find yourself always agreeing with whomever you last spoke with, that's bad. Develop the confidence to stick with your convictions—it will let you be courageous when you're right about something important that most people don't see.

Don't fall into the trap of productivity porn. Many people spend too much time thinking about how to perfectly optimize their system, and not nearly enough asking if they're working on the right problems. It doesn't matter what system you use or if you squeeze out every second if you're working on the wrong thing.

Prioritize in a way that generates momentum. The more you get done, the better you feel, and then the more you get done. Start and end each day with something you can really make progress on.

Most meetings are best scheduled for 15-20 minutes or 2 hours—the default of 1 hour is usually wrong and leads to wasted time. Avoid meetings generally, but keep enough space for chance encounters: 90% of random meetings are a waste, but the other 10% make up for it.

Delegation principle: everyone else is also most productive when they're doing what they like. Figure out who likes (and is good at) doing what, and delegate that way—don't dump on others what would drain you.

Most people don't value their time enough. Altman is surprised by how many people making $100/hour will spend a couple of hours doing something they don't want to do to save $20.

Overcommit a little bit—it makes you more efficient at everything and trains you to avoid distractions. But overcommitting a lot is disastrous. And never neglect family, friends, or things that clear your head for productivity; that's a net loss because you'll be less happy.

A full-spectrum LED light for 10-15 minutes most mornings while catching up on email is 'a ridiculous gain.' Of all the physical optimizations Altman tried, this is the one he says to try if you try nothing else.