1. Not being prepared

There is no excuse with today's technology to go into an interview without doing basic research on the company interviewing you, their executives, products, customers, and competitors.

Make sure you visit the company's website and review it thoroughly. If time allows, request the firm's marketing literature or investor relations' packet. Try to find out where it stands in the market and what its concerns may be for the future.

Check out research databases and business publications, and talk to your friends and colleagues to uncover more information.