7 First-Impression-Destroying Mistakes During a Job Interview

Gary Burnison is CEO of Korn Ferry and the author of Leadership U: Accelerating Through the Crisis Curve.

It's a statistic you've probably heard before: It only takes a few seconds for people to make a judgment about you, especially when it comes to job interviews.

During that very short time, a hiring manager will make crucial determinations about you, including your likability, your trustworthiness, how aggressive or passive you seem and how well you would fit in with others on the team.

As the CEO of a large job recruiting firm, I've seen a lot of sloppy job interviewing mistakes in my decades-long career. Here are some of the biggest that will instantly destroy a first impression:

1. Lying, exaggerating or inflating

You tell the hiring manager that you're still working at your last job, even though you've already quit, or you were fired. You want to appear more desirable, so you make it seem like you're still at that company.

Big mistake! Lying is disrespectful to the interviewer, and you can never recover from it. Even some of the best CEOs and employees have been let go — it's not the end of the world.

Someone will verify the facts of what you say, so always tell the truth. People want to know who you are, not discover who you aren't.

2. Arriving late

You don't want the very first thing you say to the hiring manager to be: "I'm sorry I'm late."

Whether it's virtual or in-person, don't be that hapless person who shows up late because they got lost or underestimated the travel time or had tech issues.

Arriving late is rude to those you've kept waiting. It also gives people a taste of what it would be like to work with you — and by not being punctual, you're telling others that you're unreliable.

3. Having no relevant examples of accomplishments

The interviewer asks you to elaborate on the accomplishments you've listed on your resume, and because you're nervous, you mind goes blank. You stumble along, maybe even reading from a copy of your resume.

But the interviewer is listening for specifics to determine how you match the demands of the job and how well you would communicate with colleagues and clients.

• The examples you give should cover four key areas:
• The challenge (or opportunity) faced
• The actions taken
• The results achieved
• The lessons learned from the experience

4. Talking too much or too little

The interviewer asks you a question that you're not prepared to answer: "Tell me how you would handle [X] challenge…"

In a panic, you either you go on and on, hoping that you'll say something relevant, or you give a short answer and then go silent. Yikes!

The best way to prepare is by rehearsing. Do a mock interview with a mentor or friend and practice giving clear and concise responses to common interview questions. (Don't forget to ask the interviewer your own questions as well.)

5. Appearing desperate

Nonverbal cues like sitting on the edge of your chair or saying things like "When will I hear from you?" can radiate desperation.

It may also raise doubts about your abilities, your fit with the organization and why others haven't hired you.

Some quick body language tips that will make you look more confident:

• Make eye contact: You'll appear friendlier and more focused.
• Avoid looking down: You'll appear distracted or lacking in confidence.
• Arms free, not folded: You'll project openness, while keeping your hands free to gesture.
• Sitting forward/back: Leaning forward helps you present your ideas. If you lean back while listening, keep your posture open.
• Smile: You'll convey happiness and confidence, while making others feel good about themselves.

6. Bringing something to eat or drink

If the receptionist or interviewer offers you water, it's fine to accept.

In fact, you should ask to help, just as you would if you were a guest in someone's home. Where are the glasses kept? If there's a water pitcher on the table, offer to pour for your interviewer.

But never bring your own coffee, soda, snack or anything else. I've been in several interviews where candidates explained that they were on their lunch break and asked if they could eat while they talked. Super sloppy and a huge turnoff.

7. Not having a 'Plan B'

If your interview is a video conference, test the technology ahead of time. Have a backup phone number in case of access issues or technology failure.

Be aware that some video conferencing systems have a two- or three-second delay between the visual and the voice communication. Allow a little time in the give-and-take of the conversation.

Also, do you know the required passwords? How do you look? How do you sound? How's the lighting? Are there pets or kids in the background?

When you prepare for the worst, it's more likely that everything will go smoothly.

A version of this article appears on cnbc.com.