The 10 most common interview mistakes and how to avoid them

You can do everything else right in the interview, but if you fall into one of these common interview mistakes, you could cut short your chances of being offered the job. Following are the ten most common interview mistakes and what you can do to avoid them:

Interview mistake #1: Lack of preparation about yourself. Most people assume that they know themselves well ("After all, I've been living in this body my whole life...") and do not take the time to prepare themselves for the interview. Unfortunately, this lack of preparation becomes painfully obvious in the stammering, the fillers (Um, ah, well, like) and broad answers lacking depth that are used to cover up this general lack of readiness.

How to avoid this mistake: Don't just read over common interview questions, do a mock interview. It doesn't have to be a formal mock interview or with a professional interviewer. You can do it with a family member or friend, just give them a list of standard questions. The key is to have a video camera placed behind the interviewer focused on you. Then watch the results. Better for you to make the mistake on video (which can be easily reviewed and erased) than in front of the interviewer (which cannot be erased).

Interview mistake #2: Lack of preparation about the employer. This tends to happen most often with brand name employers where you think you know the company because you use their products or services. I used to work for Amazon.com and candidates often felt they knew our company and our jobs because they ordered products from Amazon. Being a customer is helpful, but it's not even close to understanding the depth and breadth of the company.

How to avoid this mistake: Take time in advance to do your research. Not just what the employer provides you about the employer, but digging deep to understand the company and their key differentiators. What makes them unique and different? How do they add value in the marketplace? Who are their primary clients? What is their reputation? What is their mission? Know the employer as an insider, not an outsider. "What do you know about our company?" should be answered with a level of detail that shows you have not only done your homework, but to show you have exceeded expectations.

Interview mistake #3: Lack of preparation about the job. The candidate knows the job title, yet little else about the job or how it impacts the employer. The candidate ends up interviewing to the job title instead of the actual role, making fatal assumptions along the way. Different employers have different roles, even for identical job titles.

How to avoid this mistake: Read, know and understand the job posting in detail. The job posting will contain snippets of information about the job and the key success factors for the role. Even better, if you have an internal connection at the employer, ask them about the role and the key needs for the role. If you can portray your background as filling those needs, it will help the interviewer to make the connection toward clearly seeing you in that role.

Interview mistake #4: Arriving late. Candidates are typically traveling to a new and unfamiliar new location, taking a new route and there can often be unexpected delays outside of your control. Being late either means that someone will be shortchanged on their time meeting with you or it may move back the entire interviewing schedule for the day.

How to avoid this mistake: Plan to arrive outside the employer location at least 15 minutes early (important: allow time for potential delays, especially traffic and parking) and walk in the front door at least 5 minutes early. If you are early, take time before entering the employer building to review your resume and notes one last time. And keep in mind that it may take time to get past the front door, so arriving at least 5 minutes early allows time to move you through the building(s) to get to your interview on time. Have the address and directions printed out and don't rely exclusively on GPS to get you there--many companies have addresses that are not standard addresses for GPS.

Interview mistake #5: Not dressing the part. Interview dress is contextual to the employer. Meaning that what may be appropriate interview dress for one employer may be inappropriate for another employer. You need to avoid being both underdressed and overdressed.

How to avoid this mistake: Simple: if you're not sure, ask, and if you need to err, err conservatively. In some industries, there is a clear standard on interview dress. However, as many employers are migrating to more casual dress, interview dress protocol is sometimes relaxed as well. But while an employer may be business casual, they may still expect you to come in business dress for the interview. If in doubt, just ask. The Recruiter who setup the interview is usually happy to give you guidance. If you are unsure, err on the conservative side. Few companies will fault you for overdressing for the interview, although underdressing for the interview can be a potential knockout factor.

Interview mistake #6: Speaking in generalities. "I'm a hard worker. I always put in extra time on my projects." Sure you do. Everyone says that. Prove it. Generalities may work well for politicians, but they don't work well in interviews.

How to avoid this mistake: Speak in specifics. "I'm a hard worker. In my last project to deliver a new product on a short deadline, I put in the extra time needed to make the delivery date. Our customer was extremely pleased with my above-and-beyond effort and put me in for an employee award. May I show you a copy of the certificate?"

Interview mistake #7: Talking too much. Or too little. Taking one question and making an entire interview out of it. Or even worse, making the interviewer struggle to get more than a word or two out of you in response to the questions. On the other end of the spectrum, answering questions with basic responses (yes/no) without any details, forcing the interviewer to continually pull additional information.

How to avoid this mistake: It's a balance to answer the right amount for each question. The best approach is to answer the question, follow it up with a behavioral example, then ask the interviewer if they would like more details or another example. This will keep the flow of the interview going forward with the right amount of information.

Interview mistake #8: Getting personal. I really do not want to know that you bagged a 12-point buck last weekend. Or that you're a shopaholic. Or that you have been abducted by aliens. OK, on that last one, I guess I really do want to at least hear your story about that, but it will not help you get the job.

How to avoid this mistake: You should be personable, but not personal. There's a difference. You should strive to make a personal connection with the interviewer by being a real person, not by giving away personal information. Keep your responses focused on the professional aspect of your background and how it ties in with meeting the needs of the employer and the job.

Interview mistake #9: Not asking for the job. Well of course you are interested in the job, otherwise you wouldn't be there for the interview, right? Wrong. Interviewing is a two-way street, so it's not just about whether you can do the job, it's also about whether you are actually interested in the job and want to do the job. Do not assume that is a given.

How to avoid this mistake: You have an opportunity, at the end of the interview, to state two things that the employer needs to hear: 1) I can do this job; and 2) I am interested in moving forward to the next step. And it can be stated that simply: "I love what I've heard about your company and this job. I'm confident that I can perform well in this role and I'm very interested. What are the next steps?"

Interview mistake #10: Lack of follow up after the interview. The interview is over and now you sit back, waiting for the phone to ring or the e-mail to be sent. After all, you've done your part, now it's up to the employer? This is a big mistake and a lost opportunity if you wait for the employer to make the first move.

How to avoid this mistake: Ask each interviewer for a business card at the end of the interview. If you have a business card as well, do an exchange. Then send a personalized thank you e-mail to each interviewer that evening, both thanking them for their time and reiterating your interest in the role. This also provides you with the opportunity to add more detail about that one example you wish you had included in the interview.

By understanding these common interview mistakes, you can avoid these potential pitfalls during your interview. Keep your interview focused on presenting the best impression of you and your ability to do the job.