Structure the proposal around what's requested and the review criteria. If you know the review criteria, be sure each point is covered as fully as possible. Be on time and be complete. Reviewers find it easy to discredit a proposal if it's late or incomplete. Make your proposal visually appealing and as short as possible.
Reviewers often have hundreds of proposals to read.
Make it easy for them to focus on your important points. If a specific format is requested, use it. To set the stage, start the reader with an appreciation for the importance of the issues and a vision of how you plan to address them. Explain why your approach to the problem is the best one by briefly summarizing the process you used in developing the response. Include such things as research consulted, experience on this issue, other people or agencies consulted and a summary of what they said, the direction of a planning committee, etc.