If you are among those people who wish to go to US, then you must read this. To have US visa is a difficult job as there are thousand of US visa application seen these days. But to get through the final interview, you must take professional help and prepare yourself for the visa interview. You must have all the documents in a right way and present yourself well. For permanent stay, apply for the immigrant visa and for non permanent stay (studies, medical treatment. etc), go for non immigrant visa. If you will work hard, I am sure you will get through.