The video is self-explanatory, but there are a couple important tips for reducing stress before going into an interview. If you have a routine, there's less of a chance that you will be thrown off by something unusual that happens the day of the interview.
First, preparation is vital. Practice is always a good idea, as it reduces the chance that you will not have an answer to an interviewer's question. (More on practicing for an interview in a future post.)
Make sure to research the company and go over any standard interview questions, so you are able to answer questions intelligently. If you're interviewing with a large company, get to know the specific division with the open position. If you're interviewing with a small company, try to find out about the philosophy and history of the company.
Also, get everything ready (clothes, plan your route, etc.) the night before so you don't have to worry about it at the last second. It is a good idea to relax, but try not to do anything that would cause a major hangover the day of the interview.
The alarm clock part is actually pretty good advice, since I've had both my main and backup alarm clocks fail on the same day. This will always happen on the worst possible day, it's a law.
While caffeine may be important to wake up, don't get too wired.
Obviously don't eat a huge lunch right before the interview. The health food "experts" always say to eat multiple small meals during the day, but this is a good recommendation for the day of the interview. Bring water too, you will always get a dry throat right before a big interview or presentation. It's inevitable.
Another tip in the video is also true: don't arrive on time. Arrive early so that you can compose yourself before you go into the interview. Depending on the site, you also may have to go through security and a couple layers of receptionists before getting to the interview. Obviously, you don't want to show up 30 minutes early, but you can wait in your car if you get there way too early.
Here's a good article that includes more tips on how to prepare for an interview.
Good luck on the hunt!