Emphasize the benefits of your approach, product or service. Make it easy for the person to do or give you what you want by highlighting a distinctive feature or characteristic that makes what you are offering unique.
Provide a solid argument. Persuade with informed and adequate support. If you present your argument convincingly, with the use of stories, statistics and evidence, then what you are trying to say will carry more appeal.
Write in the active voice. In this way, your writing appears more personal, natural and direct, fully engaging the reader in your persuasion. Mention what your approach will bring, not what will be brought.
Try to avoid dry, monotonous arguments. Add humor to your writing. A bit of humor often will refresh the reader, drawing him into what you are trying to say. Humor is a convincing element of persuasive writing.
Keep it short and sweet. Do not try to impress the reader with long, flowery sentences or extensive use of vocabulary. Short sentences and snappy arguments always work best in persuasive writing. Your proposal must be short and easy to understand.