I will be writing about design patterns.  I believe design patterns should be part of your development tool as they provide you solutions to common problems that have been encountered by other developers before you.

I will start with the most common design patterns such as: Mediator, Adapter, Proxy, Observer, Strategy, Decorator, Factory, Observer, Chain of Responsibility, Singleton, Flyweight, Facade, Template Method, Builder, Iterator, Composite, State, and Command patterns.