Here are the common mistakes that students commit in their visa interview, that I came across in various forums as well as noticed while waiting for my interview.
1) Speaking too much, using cliché, saying more than what is asked. This is the most common mistake I noticed while waiting for my interview and most of the students speaking too much were unfortunately rejected (one of these students was interviewing for usmle related observership)
Answer to the point. It is not an essay, don’t say generic words. It has to be your personal interview. Do not repeat your answers; if interviewer asks you to further elaborate do not keep on repeating what you said earlier.
Main point is to think of it as not an interview but a conversation. CONVERSE! Do not stand and start speaking a well prepared answer.
2) Saying that your sponsor is someone who is not a first degree relative. Avoid saying that your uncle or cousin is sponsoring you especially if they live in US , unless you have a solid reason to say so. Be prepared for this answer.
3) Do not say you are going to stay longer than what is required. For cs it should be 1 week or maybe 2 weeks not more. Similarly for electives it should be whatever period is required. You may get another visa later if required , it is much better than having a rejection.
4) Saying you will live with a relative or a friend.
5) Sponsorship funds should be enough
6) Rarely, interviewer might not be aware that b1b2 is used for electives(a few students shared this experience)
To this say ‘we are not considered as full time students, also we will not be paid anything for this and they just want us to be on visitors visa for those 4 week’
Take along with you the US department of state foreign affair manual page 17 18 where it clearly tells about clerkship. You can POLITELY REQUEST them to look at it, if needed.
7) Know your elective programme, the name of person who will supervise you and why you want to do that- you can say it is important for diseases found commonly in my area. Don’t say you are doing this for LOR. You are doing this to gain clinical experience, LOR is a superficial thing.
8) Know the answer to – What are your plans after this. You can say complete my degree and give exams for that and then exams for my postgraduation. Be confident and answer while looking into the eyes of interviewer.
9) Last, be confident, look into the eyes of the interviewer and don’t lie. They are very smart people and are completely aware of what you are doing, so dont be oversmart. After all none of us plans to go to US illegally. Do not change your answer like 'I may stay 5 days more', no!
Be prepared but do not make it sound robotic, it should be a conversation. Read as many forums and experiences you can it is really helpful. Practice your answers well in advance but yes it should look like a free flow conversation.