What's the biggest appeal letter mistake?

The biggest appeal letter mistake you can make is trying to appeal to the recipient's emotions rather than their intellect. While you should certainly keep the recipient's personality and preferences in mind, your goal is to craft a document that any objective reader would look at and agree with you.

Emotions are real, but they're hard to prove. And making exaggerations based on your feelings will hurt your credibility. Instead, focus on delivering a clear and concise summary of the facts with evidence to back your claims up.