This speech discusses problems that principals face in trying to implement effective school strategies, describes ongoing research in instructional management, and identifies school improvement strategies used by particularly effective principals. The first section addresses practical problems in finding the appropriate balance between high expectations and student differences, between basic skills and higher-order cognitive needs, and between strong programmatic leadership and teacher autonomy. The second section describes models for principal behavior generated from research in the Instructional Management Program at Far West Laboratory. These include the "master teacher mode" based on clinical supervision and an equally effective approach based on indirect management. The final section identifies common traits of effective principals, including visibility, systematic time management, and a clear conception of effective instruction--instruction that is based on such key features as time on task, class size and composition characteristics, task and activity structures, curriculum pacing and sequencing, and evaluation. (TE)