The main guideline for basic letter writing, such as a business letter, is to follow the standard format, which includes the sender's and recipient's address, the date, salutation, body of the letter and closing. Writers should choose a font that is easy to read, such as Times New Roman, size 12. The block format, where the letter is left justified and single spaced, is typically recommended as a guidelines, notes Purdue University.
The sender's address should only be included if the writer is not using company letterhead. Writers should generally leave an extra space between each paragraph in the body of the letter. In the closing, writers should add four lines between it and their name so that there is room for a signature, notes Purdue.