The Junior High School Management Improvement Study (JMIS) was a field experiment conducted to verify and extend findings of previous research in English and mathematics classes. Using student behaviors (on task, off task, and disruptive behavior) as criteria of management effectiveness, this study investigated classroom management practices in 26 classes (part of the JMIS experiment) taught by 13 middle/junior high school teachers. Extensive classroom observations provided information about management practices associated with smooth-running, task-oriented classrooms. These include practices for general classroom procedures, managing student behavior, laboratory procedures, managing student assignments, presenting content, and structuring note-taking. Each of these practices are briefly described and illustrated. Since no information was available about student learning gains or attitudes toward science, there is no basis for assuming that practices of the better classroom managers constitute "good" science teaching. However, it is indicated that when teachers can establish orderly classroom environments and maintain students' cooperation, student engagement in appropriate learning tasks is more likely to occur. (JN)