The document discusses the key elements and guidelines for writing effective business letters. It notes that business letters should be planned, anticipate the reader's questions, and maintain clear communication. The purposes of business letters are listed as informing, congratulating, enquiring, ordering, requesting, collecting dues, complaining, and making adjustments. Additional guidelines include using a clear "you" attitude focused on the reader, brevity, clarity, accuracy, politeness, consideration of the recipient, and positive language. Finally, the document outlines common business letter formats including block, simplified, modified block, and semi-block styles.