By Jim Donovan

by Jim Donovan

PHILADELPHIA (CBS) — Job interviews can be nerve-wracking, and a new survey from finds around half of employers know in the first five minutes if a candidate is a good fit for the job.

“It was pretty good within the first five minutes. You know, just like interacting, laughing,” said Mica McKnight about a good job interview.

HR managers surveyed said some of the top ways to blow a job opportunity are: acting arrogant or entitled, dressing inappropriately, and answering a cellphone or texting during the interview.

“I had someone take a phone call during the interview and asked me to leave my own office!” said Barry Drexler, an interview coach.

Other employers have seen even stranger situations. Like when someone bringing a child along, or when one person ate crumbs off the table, or when another sang to a song on the radio playing overhead.

Experts say you should work on not being nervous.

“Your thinking should be nothing negative, nothing fearful. Just be in the moment. Be present. And really feel strong about yourself,” said Drexler.

Also, do your homework and come prepared. Amala Lane says it helped her land her current job.

“I think one thing that helped me was that I really spent a lot of time researching the organization first,” she said.

And don’t forget good body language. Smile, have a good handshake, and make eye contact.