If you have applied early to one or more colleges, the decision letter you received might not have contained a final decision. Instead of being admitted or denied, you might be notified that you have been "deferred." That means you have not been denied, and that's good news, because it gives you a second chance to be admitted! Your deferred application will be reconsidered in the Regular Decision round of decision making.
Sure, it's not the news you wanted (an offer would have been nice!), and being held in a limbo state is no fun, but don't lose hope. You can still maximize your odds of getting in if you follow these steps.
1. Treat your deferral as a second chance. Assuming you have continued on a positive course in the first part of your senior year, you have new information that can and will make the best and most compelling application — which you've already submitted — even better.
2. Use your judgment about what additional material to send. In order of most influential to least influential, here are the five kinds of updates that can help your deferred application:
New (and good) grades
New academic honors or awards
New (and higher) test scores
Anything that demonstrates your Core Four
Anything you have done that demonstrates your interest in that college
You can, of course, also submit other kinds of updates, like additional essays, recommendations, or supplementary materials. But we're not as enthusiastic about encouraging you to submit those, because those kinds of updates get mixed reviews from admissions officers. They tend to be more of the same, and they usually serve only to make your file fatter and more time-consuming for an already harried admissions officer to get through. There's a saying among admissions officers: they dread the files that "land with a thud."
3. Submit one bundled update. Rather than sending things in dribs and drabs, assemble all your updates into one package of materials and submit them all together with a short and polite cover letter. That way, all the updates together will make a cohesive and persuasive statement about you. Sending updates individually also makes it more likely that something will be misfiled or lost. If that college remains your first choice, make sure to reiterate that in your cover letter.