I found interesting this serie of posts titled “4 big ideas in software development” according to Tim Ottinger and Jeff Langr. The serie was published monthly in Pragmatic programmers magazine:

• Code coupling, or Reducing dependency in your code.
• Cohesive software design, or Cohesion makes code easier to understand, debug, and test.
• Abstraction, or How to tell a cat from a dog.
• Software volatility, or Do most changes to your code base occur in just a few files?