Consider writing a Letter of Continued Interest if you were deferred or waitlisted. Learn how here.
If you applied early and were "deferred" to be reviewed with the "regular" pool of applicants, determine if you are required to submit your first semester transcript. If so, do that promptly. It is important that you continue to demonstrate your interest in this school by submitting a Letter of Continued Interest (see above) that includes:
updates to your application (awards, projects, extracurriculars, GPA and standardized test improvements, etc.)
why this college is a good fit for you
include any information about what you enjoyed about a visit to their campus
Check your portals before sending it because some colleges do not want one. Read this article for more on deferrals.
As accepted students notify colleges they won’t be attending, those spots are given to students on the “waitlist”.
See above for information on writing a Letter of Continued Interest.
Contact the college:
To see where you stand on the list, this does not apply to state colleges.
How often this college has admitted students from the list in the past. You can see by typing "Common data set" in their college search engine.
Express your continued interest & confirm your waitlist status.
Update the school if any grades or test scores have improved. (This doesn’t apply to Cal states, or UC’s.)
You may not learn more about your status until July.
Because your chances of being accepted are slim, you need to make other plans:
Review the colleges that accepted your application.
As soon as you know your school you want to attend, not your "waitlist" college, go ahead and accept and put down money for housing. DO NOT WAIT TO COME OFF WAITLIST.
If you come off the waitlist, colleges understand, and many colleges give back your small housing deposit!