The 4 C's for proposal writing are: * Clarity: Ensure your proposal is easy to understand by using concise language, avoiding jargon, and providing clear explanations. * Coherence: Maintain a logical flow throughout your proposal by organizing your content with appropriate headings and subheadings, and connecting ideas smoothly. * Consistency: Keep your tone, style, and formatting uniform across the entire proposal to create a cohesive and professional appearance. * Convincing: Persuade your reader by highlighting the benefits of your solution, providing evidence of your expertise, and addressing any potential concerns or objections.