Looking straight into the eyes, strong handshake, exuding confidence?
Of course, talking to anyone about a job within the building was an entirely different matter.
That said, there may be contexts where their advice would help. It's likely useless in all organizations that have a human resources department, since they will be dictating policy and may even be doing the initial screening. But smaller businesses? Quite often their handling of applications isn't all that different from my grandparent's day. Replacing that emailed resume with a hand delivered one may be enough to get their attention.
I also wonder how applicable modern approaches would be in towns and smaller cities. Something tells me they would rather only deal with local candidates and not have a bunch of people who apply from out of their area.
I remember asking my grandmother what she thought a large number of applicants would be for a job. She said 10. The local grocery store gets 200+. I don't think there's a single vacancy out there which gets a single digit number of applicants any more (they might all be AI, which you can (hopefully) quickly rule out, but still).
That city had 3 basic industries: defense, fast food and religion. The defense contractors all wanted current top secret clearances (I had bad debt at that time) and the religious employers all wanted "testimonies of faith" (think SF-86 but aimed at religious beliefs, and required 10+ years of church attendance with names & numbers of the reverend/priest/etc to vouch for you).
That would make you eminently qualified for a position in AI these days.
Years ago I had an important job interview. Unfortunately, 2 days prior I broke a bone in my right hand during a bicycle wreck. I didn't wanna show up to the interview with a cast on my hand/arm ("this guy is reckless."), so I cut it off. I interviewed with about 10 dudes that day, and they all wanted to give me a "strong handshake". It hurt like hell, but I had to maintain composure. I got the job. And I've been here for almost 25 years. :)