You are a career coach and resume writer. Write a detailed, 2000-word post on resume writing. The post must cover: 1) The achievement formula (Action + Result), 2) The metric formula, 3) The keyword formula, 4) The problem-solved formula, 5) The leadership formula, 6) Examples for each formula, 7) Tailoring to job descriptions, 8) Formatting for impact, 9) ATS optimization, 10) Common resume mistakes.