Excessive smiling in a job interview is seen for what it is--nervousness and a lack of confidence. A smiley-face person exudes phoniness, which will quickly be picked up by the interviewer. Instead be thoughtful and pleasant. Smile when there's something to smile about. Do a practice run in front of a mirror or friend.

Humor tends to be very subjective, and while it may be tempting to lead your interview with a joke you've got to be careful about your material. You probably will know nothing about the sensibilities of your interviewer, let alone what makes them laugh. On the other hand, nothing disarms the tension of a job interview like a little laughter, so you can probably score at least a courtesy chuckle mentioning that it's "perfect weather for a job interview!"

You can lose a job by wearing an undershirt or simply a little too much clothing. Sweaty palms or beads on your forehead will not impress. Sweat will be seen as a sign of weakness and nervousness. Do a practice run with your job interview outfit in front of friends. The job interview is one place you definitely don't want to be hot.

Your job is to be knowledgeable about the company for which you're interviewing. Random facts about last night's episode or your favorite blog will not get you the job. Never feel you he to fill an interview with small talk. Find ways to talk about serious subjects related to the industry or company. Pockets of silence are better than padding an interview with random babble.

Asking the location of the lunchroom or meeting room will clue the interviewer into your lack of preparation and initiative. Prepare. Don't ask questions about routine elements or functions of a company: where stuff is, the size of your cube, and company policy on coffeebreaks.

Studies show that employees lie frequently in the workplace. Lying won't get you a job. In a job interview even a slight exaggeration is lying. Don't. Never stretch your resume or embellish accomplishments. One lie can ruin your entire interview, and the skilled interviewer will spot the lie and show you the door.

If you start talking about the ideal office temperature, the perfect chair for your tricky back, and how the water cooler needs to be filled with imported mineral water, chances are you'll be shown a polite smile and the door, regardless of your qualifications. Nobody hiring today is going to be looking for someone who's going to be finicky about their workspace.

Normally the switchblade is thought of a backstabber, often taking credit for someone else's work. In an interview setting, the switchblade can't help but "trash talk" his former employer. If you make it seem like your former workplace was hell on Earth, the person interviewing you might be tempted to call them to find out who was the real devil.