Interviewing is a skill; as with all skills, preparation and practice enhance the quality of that skill. Preparation can make the difference between getting an offer and getting rejected. The biggest mistake in interviewing is not being fully prepared. It befits job-seekers to use every conceivable means possible to prepare for the interview and to allow ample time to fully prepare.
There is no one "best" way to prepare for an interview. Rather, there are specific and important strategies to enhance one's chances for interview success. Every interview is a learning experience, learning that takes place during the preparation and actual interview process.