The key to any good design is proper separation of your components.  Learn how the workhorse of agile software development, dependency injection, can promote looser coupling between the different dependencies of your application allowing for more flexibility both during development and after deployment.  Then learn how IoC frameworks, such as Windsor, can take the pain away from managing of those dependencies allowing you to focus on more important things. Jeremy Jarrell: http://jeremyjarrell.com

Jeremy Jarrell is a software developer practicing in the Pittsburgh, PA market.  He has been building enterprise applications using C# since 2004.  Aside from being a regular speaker at local user groups and code camps, Jeremy maintains a website at www.JeremyJarrell.com where he continually investigates corner cases, edge cases, and advanced usage scenarios of the language.  Jeremy is an active member of Pgh.NET, Pittsburgh ALT.NET, IEEE, and the ACM.