Each cover letter should be written specifically for each individual job you’re applying for. Employers do not look favorably on cover letters which look "mass produced", so it is important to personalize each one. Try to address your letter to a specific individual within an organization rather than "To Whom it May Concern." It is often possible to find contact information online, or you can also call the organization and ask a receptionist for the name of the appropriate contact. If it is impossible to obtain the person’s name, you can address the letter with a salutation such as “Dear Hiring Personnel”.