1. Joking around. Don't tell jokes. Don't consider it a fun opening
line or ice-breaker. The odds of you offending someone (or even worse telling a
bad joke) are too high. Don't do it. If humor is an important part of who you
are, find a way to share an interesting anecdote about a work-related event.
Not a joke.
2. Using bad words. No matter which interviewer you
get and no matter what you know about them, don't swear. Not even the minor
words. Besides the obvious risk of offending you someone, you also can look
smug and too comfortable.
3. Telling really long stories. You might be
incredibly nervous or excited to share something, but don't get caught in the
long story trap. Long stories are boring, often off topic, and slow the
interview to a terrible crawl.
4. Wearing uninspected clothes. Old twisted ties,
blouses that are falling apart at the sleeves, poor fitting shirts. No matter
your clothing fault, it sends the wrong message. And yes, the hiring manager
notices.
5. Getting too personal. We all have tough times in
life. But tough times are personal and should stay private. Whether answering a
question about a gap in your resume or explaining why your last boss didn't
like you, do everything you can to keep it objective. No emotion and no
personal stories.
7. Can't stop talking. Some people just love to talk. Are you trying to fill up time to avoid more questions? Are you just a social person? Either way, some interviewers don't know how to stop you. So you have to stop yourself.
8. Avoiding details. Sometimes an interviewer will ask the same question three or four times. They do this because job candidates don't answer them. Whether or not it's on purpose, it is frustrating for the interviewer. Often they keep asking because they believe the person has the answer and the candidate just needs some help. And sometimes they just do not want the candidate to blatantly avoid the question.
9. Unwanted hair.
10. Toughing it out. If offered a drink of water, take it. If offered a chance to use the rest room, take it. These are legitimate offers, not cruel tricks to see if you'll bite. You do not look weak by accepting a glass of water.