Pay your SEVIS Fee. Your I-20 form was included with your acceptance letter. New students with an initial entry I-20 are required to pay a $350 SEVIS I-901 fee. You must pay this fee before your visa interview. Instructions and answers to all your questions can be found here.
For your visa application: Visit the websites of the U.S. State Department or the nearest U.S. Embassy.
Prepare for Studying in the U.S. You can get great information about preparing for your studies on the EducationUSA web pages. You may even be able to attend a pre-departure orientation hosted by an EducationUSA advising center located in most major cities worldwide.
Already in the U.S.? Check in with the International Center regarding procedures to follow as a transfer student or as an applicant applying for change of status.