I love reading post-postmortems of failed start-ups, having worked on a failed start-up myself. It is always less painful to learn from the mistakes of others, so I am very happy that people are willing to share their experiences. This is one of the best examples I've read:

Postmortem of a Venture-backed Startup: Lessons Learned from the rise and fall of @Sonar

It is written by the founder of Sonar, Brett Martin, and is full of some absolute gems of advice, for example:

"You do not have 20% time. Identify your top three priorities. Throw away numbers two and three."

This resonates so heavily with my start-up experience, when we wasted weeks of development time developing features that none of our users cared about, but members of our board insisted upon. We certainly did not focus on the top priorities, not even close.

"Companies don’t get sold, they get bought. The best way to get bought is to build something of value. That’s hard to do when you are trying to sell."

We also fell into this trap in the end, trying to package up what we had to sell ourselves to other companies, rather than executing on (what I believe) was the correct strategy we had finally agreed upon to achieve user growth. More users would have made us a tastier prospect for acquisition.

A fascinating article full of insight, highly recommended.