While the admissions news might not be exactly what you had hoped for, hearing back about a waitlist position or deferral spot can be a great opportunity for you to reaffirm your interest in a college, giving yourself the best possible opportunity to gain admission in the future.
First, unless otherwise specified in the materials from the college itself, I would suggest sending a thoughtful and detailed email letter directly to your local admissions representative. In this email, you can reaffirm your interest in the college, share any relevant application updates, and make the admissions officer aware that if accepted, you would attend. Here are some quick tips for each paragraph:
Dear Admissions Committee (or specific admissions officer, if possible),
1st Paragraph: Thank admissions and the school for their consideration of your application and/or for your deferral decision. Be specific about why you are writing this letter. Briefly reiterate how strong of a fit this school is for you. If your top choice, be sure to say “if accepted, I will attend”
2nd Paragraph: Present academic and non-academic updates that have occurred since you submitted your original application (e.g., test scores, grades, awards, new activities, new job/internship, new volunteer opportunity, new position within a club, etc). Try to be as specific as possible, and go beyond only what you have already submitted within your existing application
3rd Paragraph: *Briefly* reiterate why this school is very specifically an ideal fit for you. Persuade as to why you would be a good addition at this school, this school would directly align with your academic, social, personal, etc goals
4th Paragraph: Thank again for consideration. Again mention that if accepted, you will attend; top choice school
I would also suggest sending any additional acceptable materials including letters of recommendation, unique portfolio or writing samples, etc. This can be a great time to “think outside the box” when it comes to showing both your commitment to the school as well as your uniqueness.