Are there guidelines for reference letters?

Effective references typically come from past teachers or, if you haven't studied for a while, from a current or recent employer. Your referees should not be friends or family, and they should write their letters in English. A strong letter will defend your suitability for the course to which you are applying, drawing from concrete examples of your performance in class or at work.

The referee should be able to comment on your teamwork, leadership, communication and other skills relevant to the course. In case you select a former teacher as your referee, do not necessarily look for teachers that gave you the best grades. Sometimes a stronger letter will come from a teacher that graded you more harshly, but got to know you better as a person and observed how you matured academically.