Contact your sponsoring institution and request that they apply for a visa for you.
If the institution does not provide visa assistance, contact the consulate of the country where you intend to study. Most consulates are located in Washington, D.C., within area code 202.
Request a student visa application.
Fill it out completely when you receive it and photocopy it. Send the original to the consulate and keep the copy for your own records.
Wait for your visa, keeping in mind that it usually takes from three to five weeks.