Under United States law, all applicants for non-immigrant visas are viewed as intending immigrants until they can convince the consular officer that they are not. You must therefore be able to show that you have reasons for returning to your home country that are stronger than those for remaining in the United States. 

"Ties" to your home country are the things that bind you to your hometown, homeland, or current place of residence (i.e., job, family, financial prospects that you own or will inherit, investments, etc). 

If you are a prospective student, the interviewing officer may ask about your specific intentions or promise of future employment, family or other relationships, educational objectives, grades, long-long range plans, and career prospects in your home country. Each person's situation is different, of course, and there is no magic explanation or single document, certificate, or letter, which can guarantee visa issuance.

Anticipate that the interview will be conducted in English and not in your native language. One suggestion is to practice English conversation with a native speaker before the interview. If you are coming to the United States solely to study intensive English, be prepared to explain how English will be useful for you in your home country.

Do not bring parents or family members with you to your interview. The consular officer wants to interview you, not your family. A negative impression is created if you are not prepared to speak on your own behalf. If you are a minor applying for a high school program and need your parents there in case there are questions, for example, about funding, they should wait in the waiting room.

If you are not able to articulate the reasons you will study in a particular program in the United States, you may not succeed in convincing the consular officer that you are indeed planning to study, rather than to immigrate. You should also be able to explain how studying in the United States relates to your future professional career in your home country.

Because of the volume of applications that are received, all consular officers are under considerable time pressure to conduct a quick and efficient interview. They must make a decision, for the most part, on the impressions they form during the first minute or two of the interview. Consequently, what you say first and the initial impression you create are critical to your success. Keep your answers to the officer's questions short and to the point.

It should be clear at a glance to the consular officer what written documents you are presenting and what they signify. Lengthy written explanations cannot be quickly read or evaluated. Remember that you will have 2-3 minutes of interview time, if you're lucky.

Applicants from countries suffering economic problems or from countries where many students have remained in the United States as immigrants will have more difficulty getting visas. Statistically, applicants from those countries are more likely to be asked about job opportunities at home after their study in the United States.

Your main purpose of coming to the United States should be to study, not for the chance to work before or after graduation. While many students do work off-campus during their studies, such employment is incidental to their main purpose of completing their US education. 

You must be able to clearly articulate your plan to return home at the end of your program. If your spouse is also applying for an accompanying F-2 visa, be aware that F-2 dependents cannot, under any circumstances, be employed in the United States. If asked, be prepared to address what your spouse intends to do with his or her time while in the United States. Volunteer work and attending school part-time are permitted activities.

If your spouse and children are remaining behind in your country, be prepared to address how they will support themselves in your absence. This can be an especially tricky area if you are the primary source of income for your family. If the consular officer gains the impression that your family members will need you to remit money from the United States in order to support themselves, your student visa application will almost certainly be denied. If your family does decide to join you at a later time, it is helpful to have them apply at the same post where you applied for your visa.