In the ideal world, all developers would master all development processes so that they could easily determine when another practice would help them, then execute the appropriate practice flawlessly. In reality, it's actually not that difficult to master a variety of different development processes. After all, you've probably noticed that the three major development processes share the same four fundamental phases: design, implementation, integration, and testing. The main differences between these three processes are the length of the phases and the features implemented in each phase.
If you get a good grasp on each of these four common phases and what practices can be applied to improve and expedite each one, you will have the skills required to execute these phases independently of length. In any process, you need to integrate practices into these four phases that will prevent errors from destroying your process and the software it produces. Once you're able to do this, you should be able to work effectively within any of the main development paradigms.