I believe one of the core competencies of a good developer has to be writing tests for the code they write. I've only recently begun the practice myself, but have already made several improvements in the projects I have been apart of. The two hardest bits of implementing a Test Driven Development flow in my opinion are: on-boarding the practice, and continuing with the practice.

To tackle the first problem - on-boarding the practice of TDD a few things have to be done first.