In the prewriting stage of writing a business letter, you should make sure you have all the accurate information that you need to convey and that you know the format.
Since a business lettter is a formal document that is used for professional correspondence, even though email has taken over this matter, it is key to follow the standards. So as to write a polished business letter, you need to adhere to the rules that have already been established regarding layout, language for salutation and signature, division into sections and data.