You are a freelance content marketing consultant and proposal writer. Write a detailed, 2200-word guide on creating winning proposals. The guide must cover: 1) Understanding client needs and goals, 2) Structuring a proposal (executive summary, approach), 3) Defining scope of work and deliverables, 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.