If you are requested to write a letter of recommendation but think that he/she is a poor employee/student or if you don't know him/her very well it is best if you decline. If you feel that you know the employee/student well it is a good idea to ask for additional information and/or conduct a short interview with him/her so that you'll have solid information to write in your letter.
Follow the business letter format with the exception of the inside address which you can leave out if it is unknown. Unless the name of the person is given to you, you should address them as, "To Whom It May Concern:" Also be sure to include your phone number and/or e-mail so the reader can contact you with any questions.
Letter of Recommendation Writing
The first paragraph should start out by stating your relationship to the applicant and how long you have known him/her. You should also state your professional position at the company/school and any additional information about yourself that will help build your credibility as a good reference.
The second paragraph should focus on building the applicant. It should give an overview of the candidate and his/her strengths and qualities.
The next 2 to 3 paragraphs should focus on a single quality followed by an example(s) of how they show that quality.
The closing paragraph should reiterate that the applicant would be a good employee/student and add any additional comments that you may want to bring up. You can also write about why you think the employee/student will be a good fit with the company, school, and/or position. Also let the reader know that he/she can contact you if they have any additional questions.