During my periods of job-seeking I've gotten every imaginable sort of "advice" from recruiters... from the absurd to the just plain obnoxious. One actually gave me techniques to "lie" my way past receptionists, to try to pester people inside companies. All want to stress "passion", "excitement" and other marketing-speak. They all want you to have a "30-second elevator talk" prepared to spring on unsuspecting strangers, as if you were chasing down a job in marketing or selling used cars.
Having been on the hiring side of the technical interviewing process many times, it's ridiculously easy to see someone who's been "prepped" for an interview with phony techniques and enthusiasm that just not part of their personality. It's fun to tear down these candidates and blow away all the phoniness, and get them to the point where they can just "be themselves" and start the interview over again.
What are the _real_ keys to a successful interview? How about:
Clear communication, both written and oral. A resume _should_ concisely tell the whole story. It must be complete, and clear. A strong relevant technical resume will usually get a candidate through the initial screening process, all by itself.
Be yourself. Say "I don't know" when you don't know, and follow up with _relevant_ questions if you can. If you can't, say so. Bluffing is a waste of time for all involved.
Be yourself. Don't add (or subtract) emotion, passion, etc. from yourself in an attempt to show the interviewer what you think he wants to see. No matter what a recruiter will tell you, you can't possibly know what will appeal to the interviewer. There are many ways to express energy and excitement and unfortunately, most recruiters will tell you _their_ way of doing this, and that's of no help to you.
Be yourself. You'll feel better about yourself afterward (because no matter how you slice it, interviewing is a dirty, degrading process). And if you're hired as a result, everyone will be more satisfied in the long run.