Taken from Yahoo hotjobs:
Here are 10 simple things to do that will dramatically increase your chances: from wearing the right expression, to knowing what not to say, to never ever breaking a sweat.
1. Don’t be a “smiley face.”
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.
2. Don’t be a small-talker.
Your job is to be knowledgeable about the company for which you’re interviewing. Random facts about last night’s episode of “Dancing with the Stars” or your favorite blog will not get you the job. Never feel you have 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.
3. Don’t sweat.
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. You are not applying to be a personal trainer. 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.
4. Don’t be a road block.
Interviewers are seeking candidates eager to take on challenging projects and jobs. Hesitance and a nay-saying mentality will be as visible as a red tie — and seen as a negative. Practice saying “yes” to questions about your interest in tasks and work that might normally give you pause.
5. Don’t be petty.
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 coffee breaks.
6. Don’t be a liar.
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. There’s a difference between speaking with a measured confidence and engaging in BS. One lie can ruin your entire interview, and the skilled interviewer will spot the lie and show you the door.
7. Don’t be a bad comedian.
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!”
8. Don’t be high-maintenance.
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.
9. Don’t be a time-waster.
At every job interview, the prospective hire is given the chance to ask questions. Make yours intelligent, to the point, and watch the person across the desk for visual cues whether you’ve asked enough. Ask too many questions about off-target matters and you’ll be thought of as someone destined to waste the company’s resources with insignificant and time-wasting matters.
10. Don’t be a switchblade.
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.