Dress appropriately to leave a positive impression.

Candidate #1 enters the interview smacking gum. She's late, unprepared and dressed in jeans and a blouse. Candidate #2 enters the interview in a suit. She's 10 minutes early and has printed off a copy of her resume, cover letter and references.

Given the same credentials and background, I would hire Candidate #2. While interview etiquette may seem like common sense, far too many jobseekers make rookie mistakes. In order to understand the purpose of appropriate interview etiquette, let's take a minute to sit in a potential employer's chair. Your potential employer is interested in what type of employee you will be. Are you going to improve their business? Are you going to be late every day and leave an hour early? Are you excited about this job? Interviews are a way for employers to determine how interested you are in their company and the position. Some candidates sound fantastic on paper, but they don't mesh with the company culture. People with fantastic credentials may not have the personality for a high-stress sales job. Like it or not, this is your first chance to make an impression. Making it positive and memorable will increase your chance of landing the job. Here are five deal-breakers that will ensure you don't make it past the first round of interviews:

1. You don't dress the part. In today's business world, wearing a suit to the office can seem stiff and informal. However, when you're attending an interview, you should dress to impress your future employer. Dressing up for an interview is a sign of respect. Virginia Tech's Career Services office explains that your attire represents you:

   Appropriate attire supports your image as a person who takes the interview process seriously and understands the nature of the industry in which you are trying to become employed.

   If the company you're interviewing with is a "jeans and flip-flops" kind of culture, or if you think wearing a suit is inappropriate, politely ask the recruiter about the interview dress code. It's better to ask than to be underdressed. Virginia Tech and NDSU have comprehensive dress guides for soon-to-be graduates. However, it's good advice no matter what your age. Can't afford a new suit? Organizations like Dress for Success and Career Gear can help you find an appropriate outfit for your next interview.
2. You're late. Arriving late is disrespectful. Many interview sessions are carefully scheduled. You may be rotated through multiple rounds of interviews, facility tours and informal meet-and-greets throughout the day. If you're late, it just seems like you didn't care that the interviewer took the time to schedule you into his/her day.
If you're interviewing in a location that you're unfamiliar with and you're directionally challenged, make a dry run the day before. Note if this area could get congested during peak hours. Leave with plenty of time to encounter traffic. If you're really early, use this time to relax, go over your notes and prepare. Wait to go inside until 10 minutes before the interview— you'll still arrive early, but won't appear overly eager. If you've prepared and some cataclysmic event prevents you from getting to your interview on time, call ahead and explain the situation. Your interviewer can then juggle his/her schedule to accommodate your tardiness.
3. You don't have a clear understanding of the position or the company. Prepare for the interview. The bare minimum: read the job description. Nothing shows that you don't care more than not knowing what the job is about. Many listings will have a qualifications list. If you've made it to the interview, the company obviously thinks you might be qualified. Think about situations where you've applied the skills they are seeking. These stories could be good responses to interview questions. Research the company before the interview. Read through their website and note their core values. Think about whether or not you fit into the company's culture. Write down a few anecdotes you can tell that demonstrate you will work well with the company. If you're interviewing for a job in a particular industry, certain questions may be standard. For example: management-consulting interviews often include certain types of questions that measure logical reasoning. There are books that help candidates prepare for these types of questions.
4. You have distracting nervous habits. During the interview, you want for the focus to be on what you're saying. If you're wearing jingling jewelry, smacking gum or twisting your hair around your finger then the attention is no longer on your words. The focus is on your distracting behavior. If you're unsure if you do any of these things, ask someone to conduct a mock interview. Have him/her write down any distracting or irritating behaviors you develop when you're nervous.
5. You're ungrateful. This one is simple. Write a thank you letter. It's appropriate (in most situations) to send a quick thank you email. It shouldn't be long, but it should express that you're grateful for the opportunity to interview with their company.
Image courtesy of Flickr user pescatello.