Take something that people do, and remove a step (or make that step very very easy). That's the key to a successful startup.
The best startup book is one you never open because you're too busy marketing and building your product.
Put a price on it. And sell.
Another way to think about this, and the way we talk about this internally, is that we prefer to communicate through our products.
I wake up every morning and think about how I can put myself out of business. By that, I mean I think about every way another business can disrupt my profit margins and my current successes. By thinking about what they could do, I can do it myself and innovate my own business.
I need a higher level of certainty than investors do because my time is more valuable to me than their money is to them. Investors place bets in a portfolio of companies, but I only have one life.
The most important thing you can do is to get into an iteration cycle where you can measure the impact of your work, have a hypothesis about how making changes will affect those variables, and ship changes regularly. It doesn't even matter that much what the content is - it's the iteration of hypothesis, changes, and measurement that will make you better at a faster rate than anything else we have seen.