Chipping Norton ,
An appeal letter should consist of request several paragraphs that detail about the facts and events and how exactly you wish that problem or issue should be resolved. The first paragraph must detail about you and must also give an idea about the purpose of the letter.
It is important to keep the style of the letter thoroughly in object so that your view point is understood. It is always good to keep the first paragraph short and concise.
The second paragraph should narrate the events that occurred and the reason as to why appeal should be granted. Be genuine in writing and it is always good to adopt conversational style wherever required which will offer more clarity.
Mentioning dates and times will also be an added advantage and highlighting some of the points will also help.
The last para should summarize everything which should be in agreement of the entire discussion and what you are expecting from the appeal should be stated clearly.