We’ve all heard about the importance of first impressions, but when it comes to a job interview, the data actually backs up the adage. According to a new CareerBuilder survey, 49 percent of employers know if a candidate is a good fit for a position within the first five minutes of an interview. By minute 15, that number reaches 90 percent.

One reason employers may be able to make such a quick judgment is nonverbal communication. Body language like facial expressions, tone of voice or posture can often reveal just as much as words – if not more.

According to employers, some of the most common mistakes candidates make in the interview are related to body language:

• 1.Failing to make eye contact: 65 percent
• 2.Failing to smile: 36 percent
• 3.Playing with something on the table: 33 percent
• 4.Having bad posture: 30 percent
• 5.Fidgeting too much in their seat: 29 percent
• 6.Crossing their arms over their chest: 26 percent
• 7.Playing with their hair or touching their face: 25 percent
• 8.Having a weak handshake: 22 percent
• 9.Using too many hand gestures: 11 percent
• 10.Having a handshake that is too strong: 7 percent

Not all mistakes employers have seen in interviews are so common. In fact, some are downright bizarre. As part of the survey, employers and hiring managers recalled the following strange-but-true examples:

• The candidate brought about 50 ink pens to the interview and proceeded to spread them out on the table.
• The candidate kept fidgeting and repositioning his duffel bag, which turned out to have a dog inside.
• After introducing himself by name, the candidate said, “But you can call me Tigger! That is the nickname I gave myself.”
• In answer to a question about diversity, the candidate used the term “off the boat.”
• The candidate asked if he could offer religious advice to the employees.
• The candidate asked if his wife, who worked at the company for which he was interviewing, was cheating on him.
• The candidate asked how much money everyone else makes.
• The candidate gave the reason for leaving the previous position as “kicking someone’s butt that really needed it.”
• The candidate sat in a yoga pose during the interview.
• The candidate tried to Google the answer to a question.

Needless to say, a lot can go wrong in a job interview. So how can you avoid making a potentially interview-ending blunder? Avoid any of the behavior listed above is a good start, but Rosemary Haefner, vice president of human resources for CareerBuilder, has some additional advice:

• 1.Rehearse: Preparation is your best defense against disaster. Practice your interview skills ahead of time with friends or family members, and ask them for their feedback on things like posture, handshake and eye contact.
• 2.Press “Record:” Another helpful exercise is to make a video of yourself answering common interview questions. Watching yourself can help you identify any mistakes you may be making unconsciously.
• 3.Have your “elevator pitch” ready: An elevator pitch is a 30-second speech summarizing what you do and why you’d be a perfect fit for the role – and it’s the perfect answer to that oft-asked question, “Tell me about yourself.” Make sure you are also ready to back these claims up later with specific examples that showcase your skills and experience.
• 4.Do your homework: Research the company beforehand and come prepared with questions for the interviewer. Employers want to know you’re just as interested in them as they are in you.
• 5.Just breathe: Last but not least, remember to breathe. Taking a few deep breaths prior to the interview can help relieve some of the anxiety that leads to fidgeting or other nervous tics later on.