Applicants should apply at the consular section of the American Embassy any working day, Monday through Friday, during working hours of the consular section.

Documents required are :

• Valid Passport
• One Passport size photograph (In a specified format)
• A Non-immigrant Visa Application (Form 156) available from the Consular section.  
• Other require forms. (Will depend on the country you apply from)
• Form I-20 executed by the authorizing official of institution concerned, signed by the applicant.
• Evidence of financial ability to cover the costs of the education and maintenance involved
• Visa fee to (to be paid in the currency mentioned)

When to apply :

An applicant may apply for a student Visa not earlier than 90 days before the registration date specified on the FORM I-20. If the registration date is already passed or the applicant cannot reasonably expect to arrive at the school by the registration date, the applicant should obtain an amended I-20 or a letter of extension from the issuing institution stating by what date the applicant may arrive.
After the Completed application forms along with the documents are submitted;
In most cases, the visa will be issued within a few hours or days of the submission of the application. In some instances, the process may take longer depending on the time of year, consular caseload or other factors.       

If your application is denied, you should ask the Consular Officer for a "written denial decision." This will provide you with the official reason for your visa denial.

1) Acceptance by University

Acceptance of the applicant by an institution of learning for a full course of study is essential. Evidence in support of this requirement consists of a Form I-20 (Certification of Eligibility) filled out by the accepting school, and signed by the applicant and presented with the visa application.

2) Knowledge of English Language 

Evidence that the applicant has sufficient scholastic preparation and knowledge of the English language, if required by the school to undertake a full course of study in the accepting institution. Proof of the required scholastic preparation is usually established by the I-20 from the institution involved and the entries on the form. To establish their knowledge of English, applicants are encouraged to take the “Test of English as a Foreign Language" (TOEFL), available in many countries around the world.

3) Proof of Financial Resources

This involves proof that the applicant has sufficient funds to cover the total cost of education and stay in the U.S. This implies evidence of readily available funds to meet all expenses for the first year, and of the availability of funds for the following years from reliable financial resources. To satisfy this requirement applicants may show that funds are available from the educational institution, from their personal resources or from sponsors, (normally a very close relative) who have agreed to pay for their education.
If the support is from the educational institution, in the form of a scholarship, assistantship, on-campus employment, etc.,it is usually noted on the I-20.

If the support is from your home country, the applicant must produce bank books and statements or other documents showing a total amount in your currency equal to the dollar cost of the first year, and evidence regarding sources of funds for subsequent years. If the student is not paying his own expenses, an affidavit of support executed by the sponsor and sworn before a registered authority (a first class magistrate in India) must also be presented, along with financial evidence indicating the ability to carry out the undertaking.

If the support is from outside your country, the sponsor must provide a letter from his/her bank indicating that the sponsor has sufficient funds to cover the costs involved, together with a current notarized Affidavit of support stating willingness to finance the applicant’s educational expenses. The sponsor should also provide evidence of current employment and income.   

With regard to sponsorship, particular weight is given to promises of support from immediate family members. Affidavits from less than immediate relatives and family friends do not carry the same degree of commitment as do affidavits from immediate family members and should be accompanied by a statement explaining in detail what compelling reasons the person has to carry out the promises made on the affidavit.

The Embassy emphasizes that the commitment contained in an affidavit of support is not a mere formality. The U.S. Government regards Affidavits of support to be binding, legal documents that oblige the sponsor to be financially responsible for the student during his/her time in U.S.

4) Proof of Non-Immigrant Intent (Existence of permanent residence)

It is difficult to prove that you intend to return to home country after your studies are complete even though you sincerely intend to. This is because by law, all non-immigrants