This working paper describes our thinking about the promising approaches for implementing policies at sufficient depth and scale to make a difference for young children. It begins with a brief review of research on effective early childhood teaching practices. We contend that professional development and accountability policies must have a laser focus on supporting educators to enact these practices. We then describe several "implementation factors" that determine whether policies actually support early childhood educators to consistently use effective practices on a day-to-day basis. The paper then delves into four particular "problems of practice" that state leaders are currently wrestling with as they strive to implement specific policies that affect teaching quality. We conclude the paper with a discussion of four powerful state policies that we put forth that can improve teaching quality and children's outcomes. (author abstract)