to be honest, for me, the most important thing you have to do before going for an interview is to ask yourself: why do you really want the job? and, why do you really want to work in the company? is it for the money? is it for the price of pride? These shouldn't be the main reason of why you should work for a company (although these things do matter). Anyway, plenty of research is certainly essential for success. You have to demonstrate that you're really passionate about the job and that is something you really wanna do! hope that helps