The best way to be prepared is to predict what will be asked. Most jobs have a set list of questions they’re going to ask you. You need to anticipate this. For example if you’re applying for a customer service type job it’s a good bet a lot of their questions are going to be customer service oriented. Like, “Tell me a time of when you had to deal with an upset customer, and the situation was resolved.” That’s a pretty common one. So your job is to figure out what might be asked, then think about it way in advance. Think about a time when you had to deal with an angry customer and how it was properly resolved. Then, if that question is presented, you’ll already have gone over it in your mind. You could also get a friend or a family member to assist you with this. Write down a list of questions you have, then have your friend or family member ask them of you and you respond. In this way, you’ll be better prepared for the interview. Even if the interviewer asks you questions completely different from what you anticipated, the practice will help. We’ve all heard of this method before and we all think it’s silly, but that’s okay, who’s gonna know anyways? And besides, practice makes perfect.
Also, research the company before the interview, already knowing a lot of information on the company and job for which you are applying impresses a prospective employer. It will easily put you head and shoulders above the competition.
Take something for notes as well; it makes you look better prepared!
Try to do all of these things the day and night before. Eat a good dinner, get a good night’s sleep, lay all of your clothing out the night before so you’re not scrambling around in the morning trying to find your shirt, etc. Shower the night before, do anything and everything you possibly can the night before. The less you have to deal with in the morning the better (can you tell I’m a snooze button hitter?) Even lay out a copy of your resume and a notebook(for notes) in a place you can quickly find in the morning.