If your intent is to persuade the recipient in some way, whether it's to invest money, give you a reference, hire you, partner with you, or fix an issue, create a compelling case for your cause. If, for example, you want the reader to sponsor a charity event, identify any overlap with their company’s philanthropic goals. Convince the reader that helping you would be mutually beneficial, and you will increase your chances of winning their support. Keep your closing paragraph to two sentences. Simply reiterate your reason for writing and thank the reader for considering your request.
Return address and date: (Upper right hand corner) Once upon a time, this was necessary in case the letter became separated from the envelope, but I doubt that happens much any more. Even so, this is where your reader is going to look to find your address and the date the letter was written, so it should be there. Mailing address of recipient: (Left_hand side, one line below the return address) This identifies the recipient of the letter. In office environments, letters are often removed from their envelopes and circulated; this helps the letter get back to its rightful recipient.