How can communities, associations, governments, and other organizations work better together? This chapter looks at putting polycentricity into practice for improving governance, focusing on collective action among autonomous decision centres in contexts of cooperation, competition, conflict resolution, and social learning. Practising polycentric governance may involve assessing and appreciating the ways in which a situation is already polycentric and might be improved; applying principles and mechanisms to craft specific institutional arrangements for polycentric governance; and facilitating the emergence of polycentric governance, including co-creation of more inclusive networks, common knowledge, and 'power with'.