Do One Thing and Do It Well

The Unix philosophy should be in the back of a developer's mind at all times. This philosophy should be applied to all levels of development whether it be an application, script, class, method or function. By following this rule every day in every piece of code, software will be more maintainable and reusable.

The next time you start to feel like your code is unorganized, ask one simple question: What is the one thing this piece of code is supposed to do? Make sure the code solves that problem well and refactor any excess functionality into smaller pieces.