If you are serious about building your career, it is important to ask for a recommendation when leaving your job. Even if you have another job already lined up, it is important to get a letter of recommendation because you might need it in the future. When you leave a job, it is an ideal time to ask for a letter of recommendation because your work should be fresh in the minds of your supervisors and you will not need to track them down.
Identify who you want to ask for a reference. You should ask someone who knows you well and is familiar with the work that you do. It is more important that the person writing a recommendation has solid knowledge of your work than that he has an impressive title. It is usually best to ask your direct supervisor for a recommendation rather than a top executive of the firm, unless that executive happens to know you well.
Approach the person who you would like to write a recommendation for you. It is best to ask in person. Simply ask her if she would be willing to write you a recommendation. If the person knows you well and believes you have performed good work, the answer almost certainly will be affirmative.
Provide your letter writer with details about what you want the recommendation to address. Although you cannot decide what he will write, you can offer suggestions about areas that you feel are important. Remind him of particular achievements that you made and special projects that you were involved in, and provide him with details of your future plans so that the recommendation can reflect these.
Follow up on the recommendation letter before you leave the company. If you have not received the letter by the time you leave, politely remind your writer about the letter.
Send a thank you letter to the person writing your letter of recommendation. This shows gratitude and professionalism and can shape the person's opinion of you should any future employers need to contact her as a reference.