If possible, word-process your letter as it will present you in a professional manner. Always include the date at the top of the letter and your full postal address and telephone number.
Firstly, remember to start the letter Dear _____ (and include either the panel chair's name or you could address it as Sir/Madam). The first paragraph should be an introduction to yourself and the reason for your appeal. It is important to keep your letter clear, concise and to the point.
The body of the letter should then go into detail as to why your request should be accepted into the new school. You should also attach as much evidence as possible to support your application such as any medical evidence, academic reports, sports reports, and letters from teachers etc.
The final paragraph in your letter should summarize everything that you have covered in the body of your letter. Repeat the most important points again and include your contact details. The final part of your letter should thank the reader for their time in reading your letter and for any consideration that he/she will be undertaking in your appeal process.
Finally always proof read your letter for spelling mistakes, grammatical errors and punctuation. Remember, first impressions last!