While landing an interview feels like an accomplishment, it's really the first step on the road to landing the job. How you handle an interview generally means more than your resume, your references, or anything else your potential employer might look into about your background.
An interview offers a chance for the employer to get to know you. It's where the person or people doing the hiring will judge whether your personality fits the company. Yes, they may have specific questions about your background, but an interview is really a personality check -- a test of who you are and what you might be like to work with.
Some companies value personality fit more than others do, but there are some things you simply should never do during an interview. Any of these could kill your chances of being hired.
1. Don't be late
Showing up late for an interview is not only rude, it shows a lack of planning skills. If you're not sure where you are going, do a practice run beforehand. If traffic might be an issue, plan for that and arrive (but don't go in) early.
Ideally, you want to enter the office about five minutes before your appointment. Doing so shows respect for your interviewers and that you're reliable.
2. Don't blow the dress code
Interviews require a suit for men and the equivalent for women. The only exception is if the person conducting the interview tells you otherwise. For example, the interviewer could say "I know you will be coming from work, so don't feel you need to change for the interview."
In that case, it's acceptable to wear whatever you wear to work, within reason. Don't show up for an interview in shorts and a Scooby-Doo T-shirt. Even if you have to change in a restaurant bathroom on the way, find a way to be professional.
3. Don't forget to prepare
It's your job to know about the company you're interviewing with, the job you're applying for, and sometimes the person conducting the interview. Be prepared to answer why you want to work there, citing reasons specific to the company. You don't need to memorize its entire history, but you should know what makes the company and/or the job unique and appealing.
4. Don't make it about money
In a first interview, you should bring up salary questions only if the interviewer asks you. For example, if the person says, "the position pays slightly less then your current job," it's OK to answer, "I'd be willing to consider the complete compensation package before making a decision," or to be clear that you're not willing to take a pay cut.
If the interviewer asks you if you have any questions, make them about the company and the job, not how you will benefit from taking the position. There will be time for that if an offer is made.
5. Don't forget to follow up
After an interview, you should take the time to send your interviewer or interviewers a thank-you note. Ideally, this should be sent via traditional mail, but email is fine if that's how you have been communicating.
Use the follow-up to either reinforce a point or answer something you missed during the interview. That's secondary, however, to simply thanking interviewers for their time and the opportunity.
It's about preparation
The key to interviewing is being as prepared as possible. That means doing your homework and making sure you plan for any contingency. Have multiple copies of your resume with you and have a sheet of references ready in case you are asked. Practice beforehand if you're a nervous interviewee, and be ready to answer commonly used questions.
Remember that an interview is a chance to show your personality. Be ready, but be you, and show the company why you would be a great coworker.