My old boss taught me this. Every criminal case in existence was driven by the facts. Sometimes by the law, but most often by the facts. Usually, the side with the best facts has the momentum and most favorable position. But not always. Sometimes the side who knows the facts better than their opponent has the upper hand. Therefore, Rule #24.
Often there's a plethora of information flying around and it's easy for the defense lawyer to lose track of seemingly unimportant details and get bogged down. That's why I also favor Rule #5: (Always visit the Scene), Rule #6: (Read Everything in the File) and Rule #28: (Out-work Your Opponent). It's a mistake not to know the facts and it's darn hard work to make sure you've got a complete understanding of each facet of the case. But again, even if the facts aren't on your side, if you know them better than the other guy, you might have the advantage.
Finally, juries like it when you have a better grasp of the facts. That helps you build credibility with them. See Rule #33: (Credibility is Everything). One of the best ways to persuade is to demonstrate to the jury you know more about the case than your opponent. They are more likely to trust you. And this trust is often the tipping point in the deliberation room.