Many schools across the United States are attempting to implement some form of decentralization and shared decision making. This paper identifies some of the challenges associated with implementing school-based decision making and describes ways in which some schools and their principals have dealt effectively with them. Three particular challenges face principals when implementing school-based decision making: (1) developing a clear, shared educational vision; (2) developing effective decision-making and governance processes; and (3) building well functioning teams. Findings of a study of site-based, shared decision making in 24 schools--the School Restructuring Study (SRS)--elaborates on these three problems. Suggestions for improving the implementation of shared decision making, based on SRS findings, include: increase staff/administrator interaction and dialogue; appoint key members who keep the focus on the school's mission; and participate in systematic training programs. (Contains 10 references.) (LMI)