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.
When writing an application letter, remember that you probably have competition. Your audience is a professional who screens and hires job applicants—someone who may look through dozens or even hundreds of other applications on the day she receives yours. The immediate objective of your application letter and accompanying resume is to attract this person’s attention. Your ultimate goal is to obtain an interview. As you write your application letter, be sure you complete three tasks: catch the reader’s attention favorably, convince the reader that you are a qualified candidate for the job, and request an interview.