This document discusses the challenges of designing teacher education programs focused on teaching practice. It identifies five main problems: 1) specifying teaching's core tasks, 2) choosing essential beginning practices, 3) articulating practices at an effective level, 4) managing general and subject-specific practices, and 5) addressing context. It provides the University of Michigan's effort to identify "high-leverage" practices as an example and discusses remaining steps like choosing content and assessing novice performance.