Manners in general are something that has been on my mind, actually, quite a bit, as regular readers of this tome will recall.
In relating it to the job hunt, here are a few tips that seem like common sense, but, as I heard Brian Solis say in a webinar (relating to a totally different topic) the other day, "common sense is about the least common thing there is."
1. Show up early. I don't care what city you live in or what social circles you inhabit. Fashionably late is simply not fashionable for a job interview.
2. Ask before taking notes. It seems a small thing, but it's forward to pull out a pen and paper and just start scribbling away. You want the interviewer to know you're focussed on them - what they are saying and what they are asking. A simple, "Do you mind if I jot down some notes while we speak?" will go a long way.
3. No gum. Again, this seems like a "duh". But your MatchGirl heard a case recently where someone was being interviewed and they chomped on their chewing gum the entire time. It's just gross. And, it's rude. There are times and places for your gum, but a formal situation (and no matter how informal the company, an interview is formal) is never one of them.
4. Be available. Last second cancellations of interviews, unless there is unforeseen tragedy, are not going to win you any points. Remember, you are the one that needs to impress them. Not making yourself available for interviews (or at least suggesting alternate times) is never going to work in your favor. If you have an immovable conflict, the impetus is on you to suggest alternative times - a few of them - that could work for both you and the person interviewing you.
5. Say "Thank you." Politeness counts. Be genuine in it. thank the people who interviewed you for meeting with you, Thank the receptionist who let you in for her time. You never know they company structure and you can't know whose opinion will be asked. And send a "thank you" note. A paper one. Via the US Postal Service. The moment you arrive home. That little flourish makes a big difference. It's tangible evidence of your effort and your enthusiasm. Anyone can send an email. Be different.
Sure, these tips might seem basic, but forgetting even one of them could knock you down to the bottom of the candidate pile. Competition is fierce, gentle readers. A few good manners could really help you stand out.