Don't be surprised if you request a letter of recommendation and the person suggests you write a letter they can edit and sign.  This is very common due to the simple fact many people are too busy and don't have time to write the letter cut “recommendation” themselves.  This can be an extreme advantage to you, since you can now write exactly what you want the admissions committees to hear. 

Below are some tips to strengthen a letter of recommendation.  They are divided up into two sections; the first gives some ideas for a person writing a letter for you, the second offers you tips if writing one for yourself: 

To the Applicant:

1. Remember that this person is doing you a great favor, and do not approach them with unrealistic demands or deadlines.  Always give the person plenty of time to write the letter.
    

2. If you are writing it yourself, consider all of the writing suggestions offered below, especially looking over your personal essays and making sure that there are no conflicts or needless repetitions.
    

3. Don’t be too hard or too easy on yourself, put yourself in the shoes of the person supposedly “writing” the letter and be as objective as possible.
    

4. If writing for yourself, use specific dates and experiences so that the person finally signing the letter does not need to contact you again to look anything up in their editing process. If they are writing the letter, make sure you supply them with any helpful information when giving them the recommendation request and form(s).
    

5. Though you may be writing the letter, still give them ample time to review and personalize the letter.  This means more than one week!  Also, include a list of specific areas that you want them to review when you give them a draft of the letter.
    

 To the Recommender:

1.  Choose a few positive qualities observed in the applicant.
    

2. Request the applicant to supply additional information i.e. resume, graduate goals, career goals; this will help see where they are going and you can gear your letter to complement that.
    

3. In discussing those qualities, support your statements with specific instances in which they demonstrated those attributes. Be as concrete and detailed as possible.
    

4. Review a copy of the applicant's personal statement or application essays so that your letter of recommendation will not conflict with or duplicate the rest of the application.
    

5.  Describe your qualifications for comparing the applicant to other applicants.
    

6. Try to quantify the student's strengths or rank them with other applicants that you have observed.
    

7. Include some mild criticism, generally pairing it with a mentioned strength.
    

8. Discuss the applicant's potential in his or her chosen field.
    

9. Avoid generalities and platitudes.
    

10. Discuss how well you know the applicant.—move this to the beginning of the list, it seems that such a general idea would go first in a letter.

Do you feel like you have been out of school too long and your professors will not remember you?

It has been a common problem for working professionals to obtain letters of recommendations from professors and other staff affiliated with their universities because they have been out of school so long and lost contact with those individuals.  It is okay to send a request to a professor who may not remember you, it is advised to include in the email your resume as well as any information that can be used to help them while writing the letter.  As mentioned above, your chances are the recommender will suggest you write the letter and they can fine tune it.  Professors have thousands of students over their life time and will probably remember very few, don't feel intimated to still request letters from them.

Source: www.gettingtogradschool.com