The Mikado Method: refactoring for love and profit

The Mikado Method is a structured way to make significant changes to your codebase or system, no matter what language or paradigm. Its approach eschews large, risky changes in favor of a series of small, safe changes that make your primary goal fall into place. As the authors of the Method book write:

The Mikado Method can help you visualize, plan, and perform business value–focused improvements over several iterations and increments of work, without ever having a broken codebase during the process.