HBD is a big, complex game with a user manual that, like stereo instructions, tells you how to operate the device but leaves out all the stuff that makes it cool.
When I started out with HBD, I was unemployed and had lots of time to read forum threads - stuff like Aaron/Ruth, How to Rebuild a Disaster - but even with a lot of time, there was still a steep learning curve. I am still new enough to remember what being inexperienced and clueless was like. And these forums, while occasionally useful, contain a lot of noise rather than signal.
To that end, here's a challenge to HBD vets, thinkers, strategists, wonks, long-term planners - Let's collectively put together a comprehensive HBD handbook, filled with anecdotes, statistically-supported facts, quirks and history that isn't in the User Manual.
Please put some thought into the things YOU wished you knew when you started playing HBD. Write, in detail, about mistakes you've made or things you've discovered. Include the questions that come up repeatedly come up in forum threads. Give it some substance so that we all learn something in the process. Go.