There were two things that helped me get started: pairing with a more experienced developer who did TDD, and reading Growing Object-Oriented Software, Guided by

There were two things that helped me get started: pairing with a more experienced developer who did TDD, and reading Growing Object-Oriented Software, Guided by Tests by Steve Freeman and Nat Pryce. You might not have the luxury of the first, but the second is pretty accessible, even if you don't use the particular tools that the authors demonstrate.