This chapter explores the feasibility of framing guidelines for designing and implementing agri-environmental (AE) policies of general relevance across OECD countries. It discusses various aspects of the design and implementation sequence: definition of objectives, the importance of policy coherence, the role of the reference level, the types of empirical evidence needed for sound design, implementation and evaluation, the role of the reference level, targeting, implementation and ensuring compliance, policy evaluation, institutional capacity and financial administration. It argues that potentially useful, general guidance may be feasible regarding many aspects of the process, but that its scope and level of detail would not be the same for all interventions or all stages of policy design and implementation. Given the diversity of circumstances and AE policy experience in OECD countries, guidelines should be accompanied by specific illustrative examples.