1. Pretend you have no weaknesses. Or tell me that your biggest weakness is perfectionism and you work too hard. You might as well wear a sign saying, "I'm bullshitting you." Candidates who can’t or won’t come up with a realistic assessment of areas where they could improve make me think they're lacking in insight and self-awareness … or, at a minimum, just making it impossible to have a real discussion of their potential fitness for the job. I want to know about your weaknesses not because I’m trying to trip you up, but because I genuinely care about making sure you’re a good fit for the job. I don’t want to put you in a job you’ll struggle in, and I definitely don’t want to have to fire you a few months from now. Isn't it better to lose the job offer now than the job itself later?
2. Share too much personal info. I once had a candidate tell me way too much about the sex column she wrote for her campus newspaper. If I had been talking to her at a party, I would have been fascinated, but it was inappropriate for a job interview.
3. Answer your cell phone. If you forget to turn it off and it rings, apologize profusely and look mortified. Looking mortified will make me feel sympathy for you.
4. Ask questions about the company that could have easily been answered with a modicum of research. I've had candidates say, "So what exactly does the organization do?"
5. Badmouth an old boss. I'll assume that'll be me you're talking about some day.
6. Be as quiet as possible. It shouldn't be like pulling teeth for me to get information out of you. If you're shy, I empathize, but you've got to help me get a sense of who you are.
7. Don't ask any questions. I want to know that you're interested in the details of the job, the department you'll be working in, your prospective supervisor’s management style, and the culture of the organization. Otherwise, you're signaling that you're either not that interested or just haven't thought very much about it.
8. Interrupt. It's the kiss of death in my office.
9. Don't think beyond your desire to get a job offer. Too many candidates approach the interview as if the only goal is to win a job offer. But the wiser goal is to see if you’re a mutual match, emphasis on mutual. Think of it like dating: If you approached every date determined to make your date fall for you, you’d lose sight of whether or not you were right for each other. Don’t trick yourself into believing that the job offer is an end unto itself -- focus on what comes after it.