This document provides a practitioner's guide to effective demand planning. It discusses how demand planning has plateaued for many companies despite two decades of process and technology refinement. Effective demand planning requires admitting past mistakes, continuous improvement, and carefully reimplementing demand planning technologies to better sense and shape demand. Key success factors include having demand planning report to a central supply chain group rather than sales or other functions to reduce bias. Companies must also carefully design data governance between global and regional teams. Rising demand volatility further challenges traditional demand planning approaches and highlights the need for improvements.