In the intro paragraph explain what your organizations is about and what they do to help others. In the second paragraph paint a face of one individual or a cause that has been help by your organization. Close your letter with a call to action. Also don't forget to put a marketing plan together so you can give a presentation to potential donors. Here is an organization that will review your marketing plan for free, [link removed]. Their expertise is non profit marketing. Hope this helps!
Start off by explaining your organization and what you have done, let them know what you will be able to do with their donation, thank the person/company for their consideration, and remind them that donations are tax deductible. Leave your contact info.
The name is The Winn Group