11.  Admitting A Flaw.
Some interviewers will ask, "What is your greatest weakness?" Giving a straightforward, totally honest answer is a mistake; the interviewer doesn't expect you to. It's all part of a game to see if you're naive enough to eliminate yourself from the competition: counter the question by mentioning a "positive weakness." Say, for instance, "I'm a very organized person, but you'd never know it from looking at my desk."

12.  Not Knowing Your Own Strengths.
Researching the company is only half your pre-interview homework assignment. You have to research yourself as well. "You must know your own background so thoroughly that you are prepared to answer any question about it without hesitation and in enough detail to satisfy the interview," explains Arthur R. Pell in How To Sell Yourself On An Interview (Monarch Press, 1982). "Hesitating, being vague on certain points, or groping for proper words destroys the effect you are trying to create." Make a list of ten work-related things you do well or know a lot about. Then, during your interview rehearsal, come up with graceful ways to bring them up.
13.  Asking Too Many Questions.
If you were the interviewer, would you hire someone who hijacked the entire interview and put you on the defensive?
14.  Not Asking Any.
On the other hand, when the interviewer asks, "What questions do you have?" saying that he/she has covered the subject so well you don't have a thing to ask about is a bad idea too. It makes you look uninterested, unimaginative or both. "Let's say you're interviewing for a job in real estate sales," suggests Dr. Marvelle S. Colby, who teaches career decision-making skills at both New York University and Marymount Manhattan College. "You go in, having done some research on the market and ask, "Do you expect the market in this area to stay strong?"
15.  Inquiring About Benefits Too Soon.
Ask not what the company can do for you but what you can do for the company - at least at this point in the selection process. If you seem more interested in the three-week vacation policy or the new dental plan than in actual job duties, the prospective boss may develop serious concerns about your priorities. Naturally, you have a right to know about the benefits package you'll be offered, but chances are the personnel representative or hiring manager will bring it up on his/her own. After all, an attractive benefits plan is a selling point for them. If this doesn't happen, you can broach the subject when salary negotiations begin. Explain that the offer you'll accept depends on the value of the whole compensation package (salary, benefits, bonuses and any other payments).
16.  Revealing Your Price Tag.
Did you ever fall in love with an article of clothing before checking to see how much it cost? It may have taught you to look at the tag right away so, in case the price is out of the question, you can reject the garment mentally before getting your heart set on it. Things work the same way in a job search. Let these people discover how wonderful you are before you tell them how much you cost. If they try to sneak a premature peek at your price tag, Marvelle Colby recommends that you say something like, "Yes, I have some salary thoughts, but I need to know more about what this job entails."
17.  Crying Discrimination
The problem is, not everyone involved in the hiring process knows exactly which questions aren't allowed -- and in complete innocence they may bring up a forbidden issue. Don't jump up and scream accusations. Instead, reassure him/her that you can handle all your responsibilities. Even if the intentions aren't honorable, a dramatic protest is unlikely to get you the job. If you don't get hired, then you can file a complaint. If you do, you can bring up the issue later as a full-fledged employee -- and make important changes from the inside.
18.  Bad-Mouthing Your Boss
Never, never, never say anything negative about a person or company you worked for in the past. It brands you a complainer.
19.  Name Dropping
Attempts to play "who do you know" with your interviewer have an unfortunate tendency to backfire. Drop the name of someone at the company and it could turn out to the the hiring manager's worst enemy. Announce that you went to school with the chairman of the board's daughter, Felicia, and it can come off as elitism. Even worse, the interviewer may wonder why Felicia didn't ask her dad to put in a good word for you. A much better way to use inside contacts: Ask them to recommend or introduce you to the powers that be.
20.  Energy Failure
It doesn't matter if you only slept four hours last night and are coming down with a cold. When you get to the interview, you have to appear bright-eyed and eager. Job candidates with lackluster attitudes rarely get the offer. Mental energy is what it takes, so psych yourself up before making your entrance. Some lecturers and TV talk show guests do it by playing lively music right before going on. If that's impossible, just play an upbeat tune in your head. Think of yourself as an entertainer and know that the show must go on.
21.  Handshake Failure
A limp or otherwise distasteful handshake is like bad breath, one of those things that even your best friends may never tell you about. So try this: Go to a trusted buddy and say, "If I were going to develop the world's most perfect handshake, would I make mine a little firmer, a little more gentle, a little shorter, longer or what?" Then shake her or his hand to demonstrate.
22.  Glancing At Your Watch
Clock watching gives the impression that you're late for a more important date. Avoid that problem by asking when you set up the appointment, how much time you should allow for the interview. If the interviewer asks, "Will you have time to stay today and meet with our vice president?" then you can check the time and make a decision.
23.  Playing The Hero/Heroine
In 999 jobs out of 1,000, you're being called in to work as part of a team, not to make a single-handed rescue of a botched effort. Never convey the message, "You guys have really messed it up, but I can show you how to turn this company around." Instead, stress how well your talents and experience would mesh with those of others in the department or division.
24.  Losing Your Cool
Expect the unexpected. Occasionally, interviewers have been known to test job applicants by surprising them with loaded questions or blunt comments, such as "What makes you think you can handle this job when people with twice your experience don't have the nerve to apply?" Remain calm, even though your injured ego may be fleeing for the nearest exit. Some companies like to see just how professional and unflappable you can be under fire.
25.  Following These Instructions
Now that you've absorbed the "do's and don'ts" of the job interview, feel free to set the rules aside and concentrate on what a fine job you'll do if these people have the good sense to hire you. Then relax and just be yourself.

*Information courtesy Thomas Staffing