I'd say (as someone who's just gone through the process of hiring a candidate) the article is a pretty good one. The email (vs personal handwritten note) route is probably better, because you can follow up later that day or the next evening. My suggestion is to keep the letter relatively terse, note anything memorable about the interview that's germane to the job, and try to make a reminder of who of you are that stands out — but doesn't feel like a recap of your resume or its cover letter.
If there were any weaknesses or gaps exposed in the interview, here's your chance to note (briefly!) how they aren't really a problem. If there were useful or clever questions that you've come up with about the position, this is a good place for them (as it shows you're thinking about it, and it could continue the conversation).
A subject line that either carries on a previous thread or makes it clear what it's about (not just "Thanks!") is also a good idea.
Bear in mind that if someone is interviewing candidates, their time is fairly impacted already. You don't want to be a burden or distraction.
Last thing I'd suggest is that the follow-up email is not the time for the hard sell. That's what the interview was for. A polite thank you is better than a series of bullet points as to why you're the cat's pajamas. The latter reads like too many sales pitches I delete every day.
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Here's how to leave a good impression even after the interview is over:
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The Best Way to Follow Up After a Job Interview
Most career counselors and recruiting experts will tell you that following up after an interview is a must, especially if you really want the job and want the hiring manager to know it.
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