This article aims to provide a concrete illustration of a practice-based teacher education strategy. This strategy applied to the preparation of high school biology teachers learning to enact lab lessons that enhance opportunities for students to engage in reasoning with scientific concepts. The authors conclude that the tools of the bridging approach presented in the article—the heuristic goal system and the teaching impact analysis— allow teachers to construct their own authentic representations of the components of their practice and the values and goals that hold their practice in place. As a result, the path to improvement can be made both concrete and attainable.