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.
To save your reader time and to call attention to your strengths as a candidate, state your objective directly at the beginning of the letter. Example: I am seeking a position as a manager in your Data Center. In such a management position, I can use my master’s degree in information systems and my experience as a programmer/analyst to address business challenges in data processing. If you have been referred to a company by one of its employees, a career counselor, a professor, or someone else, mention that before stating your job objective.