Most professional schools will include a required quantity of letters of recommendation (sometimes referred to as Letters of Evaluation) in their application requirements.
A letter of recommendation can be seen as a reference to your potential for success as a professional student. It can speak to your intellectual curiosity, leadership, professionalism. As you are deciding who to ask for a letter, it is important to consider your relationship and what they might say about you.
A good letter of recommendation includes information that cannot be learned from other parts of your application. Letters may be required from specific sources, such as faculty members, professionals in the field, or other individuals. Faculty members are often preferred, especially those with whom you have taken several courses, or with whom you have worked closely.
After you have identified a possible letter writer, you should then reach out to them in a professional manner such as through email or a scheduled meeting.
You should be sure to identify and confirm the program(s) to which you are applying, as well as provide any necessary information needed to compose the letter. It may also be beneficial to provide the letter writer with your resume or CV, transcripts, or other portions of your application materials for reference.
It can also be helpful to provide recourses to share with letter writers such as:
It is important to ask them for the letter early enough to provide them sufficient time to compose and submit the letter before the deadline. It is also important to consider their schedule and responsibilities in identifying the proper timeline. For example, if you are asking a faculty member, it may be best to avoid asking them for a letter during finals week as many faculty members are busy grading at that time of the year.
If they say no, there could be several reasons for their choice to decline. It could be that they would not have enough time to compose a strong letter. Or, it could be that they do not know you well enough to compose a letter that would benefit your application. It is important to have an alternative individual in mind to ask in their place.
It can be beneficial to meet with them to learn about their choice to decline. You may gain important feedback that will be helpful as you select other potential letters writers or continue the application process.