A state asked the Center on Enhancing Early Learning Outcomes (CEELO) and Child Trends to review national research on best practices that have been shown to improve results on the Classroom Assessment Scoring System (CLASS), with a specific focus on research that impacts instruction and is applicable to teachers in school and community-based settings. The state is implementing a legislative mandate to unify its early childhood education programs, including all publicly-funded pre-K, child care, and Head Start. It is seeking to build upon previous advances made in their early childhood education system by including research-based professional development models and use of effective implementation to improve instructional practice in early childhood settings. The authors reviewed the research on curriculum implementation and effective professional development interventions, identified selected examples of promising approaches to professional development and coaching, and offer next steps and considerations for policymakers.