This document provides guidance on using an ecosystem approach to decision making. It outlines 12 principles for an ecosystem approach, including considering adjacent effects, managing systems for multiple benefits, and involving all relevant sectors of society. It then discusses how to apply these principles through tools like ecosystem service valuation, regulatory mechanisms, incentives, partnerships, and case studies. The key messages are to work across natural and built environments, develop effective partnerships, frame decisions around multiple benefits, collectively apply ecosystem approach principles, and learn through experience.