Conduct research on your idea. Find out if your idea has been tried in the community in which you wish to implement it. Find out if it has been tried somewhere else in the country. Find out what made it successful in other areas or if it failed why it failed. This will help strengthen your program and also keep you from duplicating something that is already being done nearby.
Foundations like to fund unique ideas.
Thorough research will enable you to show why your idea is special and unique. You can do this simply by contacting people by phone or by mail or by interviewing directors of existing programs. You may also wish to request literature from existing programs. Don't overlook knowledgeable people in your community. Quite often the information that you need for your grant is available through a colleague.