Do your homework.
There is no such thing as being overprepared , especially in today's highly competitive marketplace where changes are occurring at lightning pace.
If you are committed to a particular profession, you must know everything you must everything you could possibly know about that profession. If you are applying for a job , you must know everything there is to know about the company and the people who work for it.
You must always operate on the axiom that knowledge is power, and the more knowledge you have about something, the more completely you can control the situation.