You are a productivity and meeting expert. Write a detailed, 1800-word post on writing agendas. The post must cover: 1) The goal-first formula, 2) The time-block formula, 3) The participation formula, 4) The decision-focused formula, 5) The pre-read formula, 6) Examples for each formula, 7) Sharing in advance, 8) Keeping meetings on track, 9) Following up, 10) Measuring meeting effectiveness.