Preparation for an Interview is much tougher than appearing for any written Exam because in written exam you can remember things and just write on answer sheets but in an interview they check your communication skills,stress handling,situation handling etc so it is better to prepare for an Interview before going to any Interview.
For a better preparation for an interview cheek this resource below.
http://www.indiastudychannel.com/resources/118145-How-prepare-for-an-Interview.aspx
