Effective classroom formative assessment helps educators make minute-by-minute, day-by-day instructional decisions. This clear, practical guide for teachers centers on five key instructional strategies, along with an overview of each strategy and practical formative assessment techniques for implementation in K-12 classrooms. The authors provide guidance on when and how to use the techniques, tips, cautions, and enhancements to sustain formative assessment. Educators will learn how to: (1) clarify, share, and understand learning intentions and success criteria; (2) engineer productive discussion and activities that elicit evidence of learning; (3) provide feedback that moves learners forward; (4) activate students as learning resources for each other; and (5) activate students as owners of their own learning.