I just finished reading My Decade in Review by Dan Abramov and as part of his article he mentions this talk by Bret Victor. I think it's amazing and want to keep a reference to it somewhere. What a better place than this 12 years old blog.

Agile or Agile Development – we hear these words more often these days. But do we really know what it is all about? How can it help us become more effective, while having lots of fun developing software? How can we use it to communicate with business people and make this communication easy and constructive for both sides?http://net.tutsplus.com/articles/general/the-principles-of-agile-development/

The Dependency Inversion Principle relates to the stability and reusability of higher-level components within an application. The principle states:_A. High-level modules should not depend on low-level modules. Both should depend on abstractions.B. Abstractions should not depend upon details. Details should depend upon abstractions._Read more here.

In my opinion that principle is really important and stays in the fundamentals of software design._In the context of the Single Responsibility Principle (SRP) we define a responsibility to be "a reason for change." If you can think of more than one motive for changing a class, then that class has more than one responsibility. This is sometimes hard to see._Read more about this principle here.

That's a great article by Robert C. Martin. It's one of those articles that really may change something in your programming. The principle is called Open-Closed and it says:_SOFTWARE ENTITIES (CLASSES, MODULES, FUNCTIONS, ETC.) SHOULD BE OPEN FOR EXTENSION, BUT CLOSED FOR MODIFICATION._More about that here.