Interviewing well depends on not only how you act in the interview room, but also on how you prepare. Looking across the entire interview process, there are six key principles of how to interview for a job. To successfully adhere to these principles, you will need to start preparing for an interview several days ahead of time.
Principle 1: Practice
In the military, soldiers drill certain movements and tactics over and over again. This repeated practice allows their actions to become second nature to them. You will perform better in your interview when you reach that point where, for any question that gets thrown at you, you hardly have to think about the response. To reach this point of mastery, you will have to think about what questions you'll most likely be asked. Then you will have to practice your responses to these questions. You can do this while sitting in traffic, taking a shower, or anywhere that you have a few minutes to yourself.
Principle 2: Confidence
When an interviewer considers you as a potential hire, if your answers express uncertainty, then the interviewer will also feel uncertain about you how you will perform. As a result, they likely will dismiss you as a candidate. Practicing extensively for your interview will boost your confidence. This includes knowing what stories to tell to demonstrate that you can effectively do the job.
Principle 3: Sleep
Your body and mind depend on food, sleep, and exercise to perform well. To be as close to fully functioning as possible at the interview, you should have more than 22 hours of sleep across the three days before (average a little more than 7.5 hours per day), and the night before, try to get 8 or more hours of sleep. If you're worried about being unable to fall asleep, exercise your body. (Here's an interesting research summary on why sleep matters.)
Principle 4: Information
The more you know about a job and a company, the better a position you will be in to get hired. If you sound like someone who already works there, the interviewer(s) will be a lot more confident in your ability to fit with the organization and deliver results. The best way to collect information is from people. You can talk to people who work there, their customers, or the other organizations they work with. You will want to learn what's coming up on the horizon, what it feels like on a daily basis to work there, and how to use the endemic lingo.
Principle 5: Attire
What you wear can impact your interview in two critical ways. First, if you don't dress in a way that the interviewer would expect, then your clothes, jewelry, or even your cologne could become an ongoing distraction during the conversation. As a result, you may be thought of less highly. Second, clothes impact personal confidence. If you don't feel like a million dollars in your interview attire, then you will be in a weaker position compared to someone who does have this confidence.
Principle 6: Friendliness
Over the course of your interview, you may meet a lot of people, including the security guard at the front desk, the receptionist, the person who leads you into the interview room, and of course the interviewers. Any one of these people could impact your hiring decision, even if it is just with a passing comment around the water cooler. Therefore, it never hurts to be nice. Furthermore, people like other people who make them happy. So, by being a happy, friendly person, you will be better liked and thus will be more likely to get the job. Quick warning: if your friendliness seems insincere, this will backfire on you, so be careful.
In order to fully understand how to do well in an interview, I recommend applying all six of these principles. Applying these practices will improve how others see you, how you perform, and how likely you are to get the job. I hope this helps you land the job you deserve, and opens the door to new opportunities.