The application for admission probably isn't the only application you'll have to fill out.  You may need to do a housing application, and you definitely need to complete the financial aid applications.

Housing Applications

Some colleges require certain students (like Freshmen and Sophomores) to live on campus.  If you're going to one of these colleges, you need to get your housing application in ASAP.  The best housing fills up fast, and trust us, you want the best housing you can get.

Even if you aren't required to live on campus, but you decide to check out dorm life, you still need to apply for housing and it is still a good idea to do it early.

Financial Aid Applications

See the Financial Aid section.  After you apply for admission, go ahead and apply for federal and state aid.  Then look into private or institutional aid. 

Even if you think your family makes too much money to qualify for financial aid, you should apply.  What have you got to lose?  If you don't apply, you might miss out on thousands!