This study is an analysis of the curriculum used to teach writing at one US high school in which outcomes for students were extremely strong. The study surfaces what was different in the approach used from what is typically understood and promoted as best practice in the teaching of writing. It does so in order to surface what elements of writing instruction are fruitful for further research. Findings identify an approach to teaching writing called progressive mastery through deliberate practice. This article articulates the five elements that constitute this approach (understanding the final product, breaking down its critical elements, creating a hierarchy among the elements, layering and progression of elements, and gradual release of scaffolds), as well as the ways they work in concert to bring about improved student writing and thinking.