A review of research and proposed models on classroom processes allows identification of four key characteristics of effective classrooms in elementary and secondary education. The four characteristics encompass (1) teacher attention to student characteristics, including prior learning and learning styles; (2) congruence among the course goals, what the teacher teaches, and the knowledge and skills assessed by test instruments; (3) the amount of student engaged time; and (4) the degree of success a student experiences on educational tasks during the school day. Three models that synthesize research on effective classrooms and instructional methods illustrate different ways the four characteristics can be applied in classroom instruction. The models include Rosenshine's "direct instruction" model, Bloom's "mastery learning" model, and a model developed at Pittsburgh's Learning Research and Development Center emphasizing classroom opportunity, motivators, structure, and instructional events. Linking the four characteristics to other aspects of schools and classrooms, such as curriculum development or classroom management, suggests that these characteristics can be used to improve instruction, teacher supervision and support, and inservice training. (RW)