Effective wait-list letters often contain three key components. First is an “update” section informing the school of recent professional and nonprofessional developments since you submitted your application. This section is your ostensible reason for writing, so it should be substantial and full of as many significant changes as you can think of (promotions being the ideal). A second key component is an “addressing weaknesses” section, where you discuss what you have been doing to compensate for any factors that you believe may have put on the wait-list in the first place. This can be tricky because you may not know why you were wait-listed or you may know why (e.g., you are an Indian Male in Technology) but may not be able to do anything about it. But if you suspect that your GMAT score was too low, then of course let them know if you’ve since improved your score.
The third key component is the “reaffirming fit” section, where you show the school that you’ve continued to learn more about their program and build your network there. Let’s look at this section in more detail. The goal is to reinforce your commitment to and interest in this school’s program but to do it in a fresh way that doesn’t repeat your essays. For example, mention how the school’s philosophy and approach match your educational preferences and goals but cite new examples of resources that illustrate this. Ideally, you will have learned about these resources personally–through a conversation or a campus visit. Talk about how on a recent (post-submission) visit you sat in on a class (Which one? Who taught it? What were your impressions?) or chatted up some second-years in the cafeteria (What were their names? What did they say?). Or perhaps you exchanged some follow-up emails with alumni or students since submitting your app and found out something new that cemented your interest. All of these personal elements will help you more than some details you pulled off the school’s website.
You want the specific school resources you mention in this part of the letter to drive home the message that this school is the best place for someone with your post-MBA goals. But more importantly, you want to show the school that you are continuing to “engage” their program and its participants. They respond to this extra personal effort. If you’re really lucky, some of the students or alums you’ve reached out to will offer to send the admissions committee a brief letter of support on your behalf. If someone does, don’t mention this fact in your wait-list letter! Letters of support lose their effectiveness if the school suspects you played a big role in getting them sent.
Good luck.