One page, six blocks: who you serve (target + positioning), the number that defines the year (revenue → leads needed, worked backward), where the budget goes (channel mix with amounts), the calendar (seasonal pushes mapped to your demand curve), who does what, and the five numbers you'll review monthly.
Build it backward from the goal: needed revenue ÷ average job = customers ÷ close rate = leads ÷ realistic CPL = budget. That arithmetic chain, honest at each link, IS the plan; prose around it is decoration.
Then make it a living document the monthly review updates: plans fail as documents and work as rhythms. The annual version sets direction; twelve monthly reallocation decisions steer.