This practitioner issue brief outlines successful strategies and recommendations for state-level policymakers, administrators, schools, and districts that are based on a 5-year evaluation study on the learning environment for ELLs in the state of California. This brief offers four critical building blocks that should be in place to effectively educate ELLs: implementing a well-defined, rigorously structured plan of instruction; ensuring that teachers are skilled in addressing the needs of ELLs; systematically using data to assess teaching and learning; and regularly adjusting instructional planning on the basis of student performance. The brief also includes a list of ten tips from the successful principals interviewed for this study and a snapshot of Valley High School, an exemplary school that made strides in keeping English language learners in school and engaged in learning at high levels. (Contains 2 footnotes.)