You are a business consultant and proposal writer. Write a detailed, 2500-word guide on writing winning proposals. The guide must cover: 1) Understanding client needs and goals, 2) Structuring a proposal (executive summary, approach), 3) Defining scope of work, 4) Setting timelines and milestones, 5) Pricing and packages, 6) Including case studies and social proof, 7) Writing persuasive copy, 8) Design and presentation, 9) Following up and negotiating, 10) Examples and templates.