In a lot of ways, your letter of interest in the New Play Directing Certificate program is the most important thing in your application. Lots of pressure, but the only good introduction is an honest one. In short, be yourself. Trying to be anyone or anything else is more work than it is worth.
Before you pick a school, you should have been selective in that choice—you should know why you want to go there, have specific goals and a plan for how the program you are applying to can help you meet those goals. All that should be in your letter of interest.
How else are we going to know anything about your passion for theatre, how much you looked into our program, and whether your expectations of the program are realistic? Your letter of interest is the best tool we have (outside of an actual interview) to help decide whether or not the school and the student will be a good team for the next two years.
Choosing a cohort of students is like casting a play. Talent is important, but so is knowing the ensemble will work well together, be mutually supportive and be good ambassadors for the institution. And if you don’t get in, that means nothing more than the path to your success might lie in another direction.
Ask hard questions of yourself and the institution. We’ll do the same—and that is going to be a very good and useful conversation to have regardless of the outcome.