"Design Pattern" or DP is really the same as "Best Practices'
(best practices for solving problems)

In Software development, DP is the same as Software Engineering   

there are about 23 different design patterns 

One example is a Singleton Pattern that uses one and only one 
instance of a class such as a server logger or a server DBconnectionManager. 

Another example is a Factory pattern that uses a factory class that would 
instantiate subclasses based on args or parms. E.g. a certain factory class
to generate, say a form given a model. The trick is knowing what the app
requires and what factories are already available [in the framework]