Show up 5 mins early, make sure your hair is brushed, clothes are appropriate, clean and wrinkle free. Mind your manners, (yes sir, no ma'am, thank you, etc) Listen to the question and don't interrupt. Put thought into your answers. Shake hands when you meet the person. I know some of this sounds like a no brainer but you would be surprised what I have seen.
Speak with confidence and basically sell yourself to interviewer. Let them know your strengths and how you can be a great asset to their company. Focus on your strengths and keep good eye contact. Knowing the companies history could prove to be a bonus. They will most likely ask what made you decide to apply there. Answering by mentioning something company is known for let's then know you invested time getting to know them.
DO dress for the job, get there ahead of time, research the company, take a copy of your resume and cover letter, sell yourself with examples of your best qualities, look them in the eye when answering, have questions for them regarding the particular job you are interviewing, show confidence, shake hands, thank them for the interview, be yourself.. DON'T talk poorly of any past job experience/person, don't answer with "ummm" or "I don't know" or "like, you know", don't be late, don't ask about days off or vacation time, don't be cocky, don't talk about personal things, don't talk too much, DON'T FORGET TO SMILE.. Good luck!!
when i used to hire people i always looked for these things, Make a resume, if you havent worked its ok make one of your school accomplishments, sit up straight and answer clearly, dont use street slang no uh huh or yeahs, yes or no, always make eye contact with who you are speaking with. Dress properly no sweats or shorts , pajamas, clothes with holes no flip flops or shoes with holes in them, dont ever say dude If you need to shake hands make it a proper one nice and firm, no one likes too shake hands with a wet noodle, be confident on the outside even if you dont feel that way on the inside and never never be cocky
FreudianSlip and guss7116 gave great answers but also you should study up on the company so you can ask questions of them. Let them know that while they're interviewing you, you are interviewing them. Ask about advancement possibilities, what resources they provide to aid you in job performance etc. It will impress the hell out of them to see you acting confidently.
many things can make you look better and knowledgeable..for example...if he asks "why do you want this job?" you would prob say for benefits and a reliable company and I'm good with people/computers.. blah blah blah..what you should really do is say something like "from what I saw from 2009-2011 you guys increased an average of almost13% gross income, 3 million dollars to be exact and continue to increase making this a reliable job..... stuff like that, your interviewer wants to see if you are smart. that's just one tip.. are many more but Im trying to study...sorry