You may be asked to write a letter of referral for a friend who has applied for a job or who is applying to graduate school. You can write a convincing letter if you're familiar with your friend's professional background, academic record and work ethics. However, referrals from friends who do not know the applicant in a business relationship do not carry much weight. If you're comfortable giving the referral, get the pertinent details and highlight her best qualities.
Get the name and other contact details for the person to whom the letter is being sent. Be careful about addressing referral letters "to whom it may concern". You want to make sure that the letter is used fo the purpose and occasion specified. Get details from your friend about the position or the program for which she is applying. This will help you to write a more purposeful letter.
Start the letter by stating how long you have known your friend and in what capacity. For example, mention if you were co-workers or if you worked together in a volunteer capacity. Stating that you served on a board with your friend when she was the treasurer means more than a letter from someone she only knows socially.
Point out the qualities of your friend that relate to the position. Cite specific examples from your experience with her.
Add other relevant information. As a friend, you may be able to attest to her moral integrity. Again, give an example.
Print and sign the letter. Do not use your professional letterhead unless you are also writing it in a professional capacity. Mail the letter to the appropriate individual.
If your friend is applying for a job at a company you know, or at your workplace, it may be more effective if she mentions your name in her cover letter instead of asking you to write a letter of referral.
Do not write a letter of referral for a friend to use unless you are comfortable vouching for her.