A character reference contains information about who the writer is, what his connection is to the person he is recommending, and specifics about that person's good qualities and skills, states About.com. Depending on the purpose of the reference, statements are made recommending or supporting the person.
A character reference is either formal or semi-formal depending on the purpose of the letter. Always include a salutation either directly addressing a person, such as, "Dear Mr. Wallis," or with a general but appropriate, "To Whom it May Concern." The first paragraph describes how the writer knows the person in question and why the writer is qualified to submit a letter on his behalf. If the writer is a personal relation, he focuses solely on the person's character.
The second paragraph is specific to the person being recommended and contains examples of his character or work ethic. The writer focuses on examples that he personally witnessed, avoiding second-hand information. If there are many strong examples, multiple paragraphs are acceptable as long as the letter is not too long.
In the letter's summary, the writer explains what he hopes the letter accomplishes. If it is for an employment or educational opportunity, the writer includes a statement recommending the person. If the letter is for legal purposes, the statement focuses on supporting the individual. The writer finishes the letter with contact information and availability, encouraging the reader to seek him out for more information. The letter is ended with a formal "Sincerely," and the writer's signature and title.