Write an introduction to the paper. Include the name of the person that the character reference paper is about, and then introduce yourself. Explain how you know the person, and why you feel you have enough information about the person to write a character reference paper. If you are doing a character reference paper on a character you do not know, such as a character in a book for a school project, use your introduction to simply talk about the character and give a few details.
Talk about the person for whom you are writing the character reference. If the point of your reference is to paint him in a good light, give as many good details as you can. If you are supposed to talk about him negatively, give as many bad details as you can. However, all details should be true. Don't say anything that is not true, or of which you don't personally have proof.
Give proof for the ideas that you talk about when you are discussing this person's character. For instance, if you say that the person is a hard worker, explain that you have been his boss for 15 years. If you say the person is a bad influence on children, explain that you have witnessed the person partaking in drug use around children. Again, all the proof that you provide for whatever statement you make should be truthful.