Coming from a human resources background it always blew me away how many people would show up for an interview completely unprepared. Whether it was the way they were dressed, didn't bring a resume or even didn't think they were going to be interviewed that day at all. The Undercover Recruiter has put together THE ONLY 5 INTERVIEW QUESTIONS YOU NEED TO PREPARE FOR check it out and make sure you're prepared.
Do you come off looking stupid when you're trying to look intelligent? Unfortunately most of us do. Check out this diagram that describes what it is people can do to help project intelligence. Check out the Wall Street Journals post on How to Look Smarter.