The truth is one of the strongest propositions.
So how about a real appeal? Not one of those fake ones with three weeks concepts plus three weeks copy and three weeks to design and endless edits by every man and his dog that waters it down. I mean a real appeal. Written, printed and posted / emailed immediately in response to a real need that tells a great story.
Do your research. Prepare the logistics and get a project team together make it happen. Meet the people, write the appeal there and then, decide what to send it with, and get it out.