Whether on the phone or in person, a job interview can be a terrifying thing. You want to come in looking professional. You want to speak eloquently and lay out the reasons why you're the right candidate for the role both in terms of your background and your disposition.

"It is very nerve-wracking," says HR consultant Stefanie Fackrell, who's worked in recruiting at companies like Google and Nvidia.

Still, she says, the most important thing is "to go in relaxed and confident," she says. It's easy to get caught up in your fears when you're there, but "I think that's where people can make mistakes," and perhaps not give their prospective employer the kinds of answers that will sway them in the direction of a job offer.

Here's what she suggests to help you stay cool and calm.

'Take a breath'

To begin with, let yourself take the interview process a little bit slow. Don't give monologues when you've been prompted to talk but give yourself a second to get a sense of what your interviewer wants to know.

Sometimes, when a candidate gets asked a question, "they're so nervous that they just hurry," says Fackrell. "They talk right away and then they aren't processing really what the question is." That means you risk not giving the interviewer the information they've actually asked for, possibly forcing them to ask you the same question again.

Listen carefully to what your prospective employer is saying. "Take a breath," says Fackrell. "Don't rush." You can even repeat the question to them to make sure you understood it.

Do 'a pre-interview power song'

Another tip Fackrell suggests doing even before the interview starts: Listen to music. Specifically, listen to music that's going to pump you up.

This can happen when you're on the way to the interview if it's in person, or it can happen when you're at home preparing for a phoner. "I do a pre-interview power song myself," she says. Her song is Outkast's "Bombs Over Baghdad."

The point is to choose something that's going to "put you in a good mood."

Your interviewers are rooting for you. They want you to succeed — that's why they invited you in in the first place. When you're there, "we just want you to put your best foot forward," says Fackrell, "to shine, to be confident."

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