Expect to go through both immigration and customs inspection at the U.S. port of entry. You may also be required to go through a pre-inspection procedure at certain airports abroad. At the immigration booth, present your passport, your SEVIS I-20 or DS-2019, your proof of Federal SEVIS fee payment, and your completed I-94 arrival/departure card (if the card was distributed on the airplane). Expect to have your index fingers scanned for fingerprint purposes and a digital photograph taken, as required by U.S. federal regulations.
DO NOT enter on another school's certificate of eligibility, as that is considered to be a fraudulent entry by the U.S. Immigration authorities.
DO NOT attempt to enter the United States on a visitor/tourist visa (B-2) unless it is designated "Prospective Student" by a consular officer. The U.S. Immigration Service rarely authorizes a change of status from B-2 to F-1, and you will be prevented from enrolling in school until your change of status application is approved, which could take several months.
DO NOT attempt to enter the United States under the visa waiver program, available to citizens from nearly 30 countries throughout the world. The waiver program is designed for tourists only, and attending school under the waiver program is a clear violation of U.S. immigration law.