If you had to list the activities most likely to cause anxiety, interview would probably be at the top alongside things like public speaking. An interview, though, tends to be extra intimidating because it has a lot in common with public speaking but, unlike public speaking, you can't just prepare a planned speech with notes beforehand. Sadly, interview anxiety tends to become a self-fulfilling prophecy: your fear that you will do bad kills your confidence and tends to make you unable to perform at your usual level. So, here are a few strategies to help you cope with pre-interview stress and, hopefully, do better as a result.
This probably sounds obvious but it doesn't just mean review the company's site and read their blog. It means find out everything you can about the company, the position, and the industry so that you'll be prepared and well-versed in any and everything. Google your interview and the company executives, find and recent news about the company, and visit all of their social networks to get a better understanding of their work and culture. Figure out exactly how your skills can benefit them and come up with a few suggestions for how you can help them. Review your resume and see how specific experiences or skills match the job description and be prepared to speak to that. Think about your work experience and come up with a few stories that will answer things like "tell me about a time you were a leader" or "what is your biggest weakness?" The more you know about the company and understand why you'd like to work there and how your skills can fit in, the less stressed you will feel when your interviewer asks a question intended to catch you off guard. Preparation also means being 100% sure you know exactly how to get to the office and how long it will take (add some extra time to be safe) so you don't feel rushed or confused when you're trying to get there in time.
Okay, so you shouldn't exactly hit the gym an hour before you interview. However, if you have time (and the ability to shower!), nothing beats stress better than cardio. Don't use this as a time to try something new and challenging that will leave you feeling sore and exhausted, but something you're comfortable with and can easily conquer. It will remind you how strong you are and that can handle anything. Plus, the endorphins will leave you feeling positive and happy and that is a great vibe to give off in an interview.
Breathing is obviously pretty useful in general, but if you're a singer, practice yoga, or play a wind instrument you've likely heard of diaphragmatic breathing. The diaphragm is a muscle in your rib cage that regulated breathing but most people don't take full advantage of it. When you take a deep breath, allow you stomach to expand rather than having your shoulder rise. This will help you take the fullest breath possible and will help relax your body.
Before your interview, make a playlist of the songs that make you feel invincible and bring it with you for your commute- whether that's listening to an iPod on the train or blasting it on your car stereo. It's hard to feel nervous when you're singing along to empowering music.