Scott Mattocks has posted the next in his "LUCID development" series of posts with the next letter in the acronym, "C" for Configurable:
As code moves through the software development process, it moves through different environments. In many cases, the full details of then environment may not even be known at the time development starts. Getting your code to change its behavior on the fly is only possible if you have carefully and thoughtfully interleaved configuration parameters into your code.
He talks about handling configuration for external systems and the responsibility that comes with access to the connection information for resources. He makes some recommendations as to where to start if you're looking for places in your code to change how configuration options are used - low hanging fruit like code that accesses external systems.