Making sense of design patterns, best practices, etc

I read a couple of posts the other day from Jeff Attwod (The Ferengi Programmer) and Rob Connery (Patterns, Purists, and Sinkholes) that were a little more thought provoking than average.  They're both talking about how to make sense of all of the 'best practice' advice thats out there, how to know when you're allowed to break the rules, and the various troubles that you can get into on both sides of that coin.  Certainly you can quickly get lost when using the design pattern hammer for every problem and often you just have to 'get things done, NOW!'.  But obviously those best practices and principles (like Bob Martin's  SOLID principles), have a ton of value and really can't be ignored by any professional developer.  So how do you know when to break the rules?