Dependency Injection is a hot topic these days. If you aren't familiar with DI, I suggest you read Martin's paper. If you are familiar, don't worry, I'm not going to rehash it.
Actually, I want to point you in the direciton of Pico Container. PicoContainer is a lightweight container that can modularize how dependencies between parts of your application are laced up. Additionally, it will improve the testability of your code and improve how components are configured in application.
Lastly, while reading the Pico Container documentation I came across this page about creating classes that are Good Citizens. Even if you never use Pico Container, this page is well worth your time. The ideas presented about being a "Good Citizen" aren't specific to Pico, but are specific to good code.