The first paragraph as such in the letter should cover up the person’s introduction. The other thing that should be covered in the first paragraph is the purpose of the letter. One should make sure that the right words and proper language is used.
The second people should pour light on the purpose. The purpose should be elaborated a little bit. This is the right spot where in you can write about what you want to portray and also as to what you wish to expect from the party in front.
The last paragraph should have words that come across as very pleasing to the reader. The last thing would be a little reminder about the purpose, just to end the letter.