Ask for information about the person who requested you to make a character reference. Get a copy of his resume, and try to learn what he does outside the workplace, the organizations he is involved in, and his hobbies. Knowing these should give you an idea of the holistic development of the person and the skills you probably didn’t know he had.
Also, ask for information about the job the person is applying for. Having knowledge of the responsibilities and values the job entails will help you evaluate if he is qualified for the job.
Address the letter as personal as possible, so that means you would also have to ask for the name of the prospective employer. While writing “To whom it may concern” is not a mortal sin, a personalized heading would make a more powerful impression to the employer.
Verify that the individual has worked for you. Include the range of dates he was employed and probably his salary. Explain the person’s job description in your company and the tasks he performed. Specify the length of you relationship and in what capacity, as well as how that relationship makes you eligible and credible to write a reference on his behalf.
Justify what you think qualifies the person for a particular position. If the person was an asset to the company, do not hesitate to mention it. Back up your words with specific examples. Keep comments toned down. A reference letter is one where if you don’t have anything good to say about the person, you can say nothing at all.
Comprehensively discuss the person’s positive attributes. Choose words carefully. Using too many glowing terms about the person makes prospective employers doubt the legitimacy of your recommendation. Don’t use the adjectives “nice”, “good”, and “satisfactory”. Don’t suggest a sense of confidence in the person.
Emphasize a variety of traits deemed necessary to employers. Highlight the person’s leadership, versatility, dynamism, ability to communicate, and his self-confidence.
Close the letter by offering to give further information if necessary. Provide information on how the prospective company can contact you. Make sure the letter is typed and proofread.