How to Ask for a Reference in Academia
Nearly every university student at some point needs to ask for a letter of reference for some purpose. You might be applying for a job inside or outside of academia, or for postgraduate study, or for funding to support study or research. Lecturers consider it their duty to provide support to students in the form of letters of reference, so you should not be shy about asking for one. However, there is an established etiquette around this that you should learn and follow.
Not all references are alike. When you need a letter of reference, you should investigate carefully and make sure you understand the nature of the reference that is needed, and that you communicate this clearly to the person whom you are asking for a reference. References can be of very different types; many non-academic job applications require the person to merely fill out a form, whereas the standard academic reference involves writing a one-to-two page letter detailing the nature of the letter-writer's relationship to the applicant and the applicant's qualifications. In some cases you are asked to merely provide names and contact information so that your reference-writer can be contacted on your behalf, while sometimes you are expected to personally arrange for letters to be sent. Sometimes a reference can be uploaded to an online form or sent via email, while sometimes it must be provided to the applicant as a hard copy and passed along with the application.
It is YOUR responsibility to find out all the details and to provide as much information as possible to the person whom you are asking to be a reference for you: whether a form or a full letter is needed; how the reference is to be delivered; to whom the reference should be addressed (provide a name with title and a full address); when is the deadline for the reference. Never put your reference-writer in the position of having to go digging for these kinds of details.
Short notice is bad form. You should always give plenty of advance notice to anyone from whom you are asking for a reference. If you need a university lecturer or tutor to compose a letter on your behalf, and if it is the first time you have ever asked this person for such a letter, you should give that person no less than three weeks advance notice. Writing a letter takes time, not just for composing it, but for doing a little background research to recall your past work and qualifications - remember that university lecturers work with dozens and even hundreds of students. Also, university lecturers have very busy schedules with multiple deadlines to meet, and they have to incorporate your request into their workflow. Once a lecturer has written one letter for you, subsequent letters that you might need can be produced with less advance notice - but you should always allow at least one week. Never ask for a reference with only one day's notice - it is bad form to put your lecturer in the position of having to meet so short a deadline, and such a request reflects very badly on you.
Reference requests are a face-to-face matter. When you are asking a university lecturer or tutor for a reference for the first time, it is not sufficient to merely send an email with your request. You should arrange an appointment to meet personally with the person in order to explain what your goals are and to establish the fact that you would like to ask for continued support from the person as a reference-writer. That meeting provides an opportunity for your potential reference-writer to collect information from you that can be used in composing a letter. Once this relationship is established, future letters of reference can be requested with just an email or telephone call.