We have long known that some teachers are much more effective than others. Highly effective teachers and their students thrive in ways that have been hard to replicate on a large and consistent scale. In this paper, we read across studies to identify actionable lessons about what it will take to staff all schools with highly effective educators and to surface directions that are particularly important for further inquiry. Our analysis surfaces six cross-cutting and interrelated themes, suggesting the following key areas of consideration for teacher effectiveness: (1) match and fit; (2) professional environments; (3) collaboration and social capital; (4) coaching, mentoring, and personalization; (5) instructional materials; and (6) principals.