interview, body language, fidgetingEje Gustafsson/flickrFailure to make eye contact and playing with hair are two of the most common body language mistakes people make in job interviews.

Your dream employer is hiring, so you do your homework, submit your résumé, land yourself an interview, and kill it in the hot seat. You're pretty confident it's in the bag.

But on your way out, you shake the interviewer's hand, thank him for his time, and completely blow your chances. 

How? The handshake was weak and you failed to make eye contact.

That's right: These simple mistakes can cost you the job, according to body language expert Tonya Reiman, author of "The Power of Body Language."

"When someone first meets you, an evaluation is quietly and unconsciously taking place," she explains. "There is an incredible amount of processing going on as millions of neurons in the brain are activated and working to determine if they believe you to be credible, trustworthy, and likable. That impression is based primarily on your nonverbal communication."

So, from the moment you arrive for a job interview until the moment you leave, you need to be keenly aware of your gestures and nonverbal cues.

Here are seven common body language mistakes that can cost you the job: