This document discusses principles of effective professional development for teachers and the role of teacher-researchers. It outlines that effective professional development is driven by a classroom vision, helps teachers develop knowledge and skills, mirrors student learning methods, builds a learning community, develops teacher leadership, and is continuously assessed. It also describes that teacher-researchers collect and analyze artifacts from their teaching practice, share observations with peers, and present findings to colleagues to improve instruction. Finally, it discusses that teacher cognition develops from social and cultural classroom activities and interactions with students.