"1. Start with Why"

"“People don’t buy what you do they buy why you do it.”"

"2. Pareto principle"

"3. Eating your own dogfood"

"4. Velocity"

"In product development you want velocity, and the direction you want to be traveling is towards your strategy."

"5. Second-order thinking"

"As opposed to first-order thinking, which is primarily about the cause-and-effect of the immediate decision you are facing, second-order thinking involves asking “what happens next?”."

"6. Reversible vs. Irreversible decisions"

"The idea is that there are two types of decisions — reversible, which make up the majority of decisions and can be easily changed later, and irreversible, which are hard to change."

"Reversible decisions should be made quickly and without perfect information since you can adjust the course quickly."

"Irreversible decisions should be made carefully and require more extensive information gathering before reaching a conclusion."

"7. Opportunity costs"

"8. Paradox of choice"

"Instead, focus on smarter defaults and balance presenting the right options to customers at the right times to avoid decision fatigue."

"9. Inversion"

"Instead of thinking through why something will work, think about the reasons it won’t."

"Instead of forecasting from the current state and projecting forward, try backcasting by thinking backward from your end goal."

"10. Probabilistic thinking"

"Probabilistic thinking is the process of using logic and estimation to guess the outcome of a particular event."

"11. Do things that don’t scale"

"Doing things that don’t scale is a reminder that putting in the work manually is often the faster path to learning."

"12. Secure the beachhead"

"13. Vitamins vs. Painkillers"

"The key to product positioning and selling is identifying the real pain point your product solves, who experiences the problem, and the “trigger” that causes the problem."

"14. Maslow’s Hierarchy of Needs"

"15. Theory of constraints"

"Question 1 — What people problem are we trying to solve?"

"Facebook example — “I want to talk about an interest with other people who are also interested, but I don’t know where to find these people”"

"Question 2— How do we know this is a real problem?"

"Question 3— How will we know if we’ve solved this problem?"

"What evidence is there — qualitative and quantitative — that this is a problem worth solving"

"Set measurable goals, metrics, and milestones before launching anything to users."