Demand plans fail when campaign calendars and supply decisions are disconnected. The fix is a monthly operating rhythm where marketing, sales, and operations all sign off on one number.
Start with a base forecast from recent run rate, then layer campaign uplifts with confidence bands. Use conservative, expected, and stretch scenarios to prevent overbuying before promotions.
After each campaign, run a post-mortem that compares planned vs actual units and margin. Feed that variance back into next month assumptions so forecast accuracy improves over time.