It’s said that we have less than 30 seconds to make a first impression. So if your CV has got your foot in the door but you’re worried about putting your foot in your mouth, avoiding these five no-nos can help you make, rather than break, your face-to-face.

Over- Or Under-Dressing

On the formality scale, etiquette coach and founder of Speak-Well Myles Usher suggests that job interviews are “on the same level as meeting the parents of a new partner for the first time.” We all know that wearing joggers is probably a bad idea, but over-dressing can be just as much of an issue. By wearing something completely off-kilter with the rest of the office, you’re making it tricky for the person doing the hiring to see you fitting in.

Catherine Conlon of recruitment website Monster agrees that “you should be the focus of the interview, not your clothing.” So stick to smart basics and don’t over-egg it. If a suit doesn’t feel right, then a pair of well-tailored trousers, a white shirt and a crisp navy jumper will work in any situation.

Blowing Your Own Trumpet

Being polite and interested in the person who is interviewing you may seem obvious, but even public speaker pros can get wrapped up in trying to sell themselves too hard. Coming across as cocky rather than confident is a nightmare scenario that is hard to come back from, so Usher suggests asking about their career path and how they like the company.

“This is a technique that is most useful in the ‘do you have any questions for us’ section, as it gives you something to say that suggests a genuine interest in the culture as well as the work.” The person who’s interviewing you will likely be working alongside you for 40 hours a week, so put yourself in their shoes – do you want to sit next to a self-absorbed bore for the best part of your Monday to Friday?

Open Door Policy

While you’re trying to get in the zone in your own head, don’t forget that the interview starts the moment you step inside the building. Jana Eggers, CEO of Nara Logics, says that regardless of how the formal chat went, she always gets feedback from the receptionist: “I want to know if someone comes in and isn’t polite, if they didn’t say hello or ask them how they were. It’s really important to me.”

So swap cramming last-minute company policy facts on your phone for water-cooler chat and it may just clinch you the job.

A Warm (And Clammy) Welcome

Of course the universal guarantee in all job interviews regardless of industry is the handshake. Wherever you stand on the firm scale of ‘shakes, there’s one thing you can do that will make it universally more reassuring: “Dry, warm hands inspire confidence while cold, clammy hands are a big, unconscious turn-off” says Emmie Martin of Business Insider.

Applying deodorant to your palms and warming them under the hand-dryer might seem like an odd pre-interview ritual, but psychological studies have shown that even holding a warm coffee makes someone feel more positive about the person we’re talking to, so it’s not all pseudoscience.

Clean It Up

According to recruitment platform Jobvite, 93 per cent of those looking to hire will stalk research an applicant’s social media accounts before meeting them face to face.

It’s not just the sloshed-on-a-stag-do posts that put off employers – two-thirds said they would also be put off by bad spelling and grammar, regardless of how spotless the CV was. Time to update those privacy settings and un-tag your Magaluf 2013 album for good.

Be Interested

It’s the end of the interview, you think it’s gone pretty well up to now – and the interviewer asks you if you have any questions. If you shrug and say no, that’s going to leave a good interview on a bit of a sour note.

Prepare a list of questions beforehand, and be prepared to ask whichever ones weren’t covered in the interview. There’s always the generic, “What’s the office culture like here?”, or “How do you find working for this company?”. Asking questions about the company also shows that you’re taking it seriously, and that you’ve got an analytical mind.

Bottoms Up

You might feel like saying no to a glass or water or coffee is the polite thing to do – you don’t want to be a bother. But many employers advise the opposite. Saying yes to an offer puts you in good stead, and gets you started on a reciprocal relationship with your potential new boss. Accepting their offer will also put them at ease, too.

If you’re really nervous, though, stay away from the caffeine. And definitely avoid alcohol at any cost. One study found that, in interviews over dinner, candidates who stuck to water, rather than wine, were consistently rated more favourably by their interviewer. Duh.

Practise Makes Perfect

There’s nothing worse than going into an interview and rambling for half-an-hour. Think of the key questions you might be asked, and practice answering them clearly and concisely.

Your interviewer will thank you for it – and you’ll save more time to get away from the script and talk about more important things.

Don’t Be Awkward

Lingering goodbyes are never good – give a firm handshake, thank the interviewer for their time, and be on your way. Do not, under any circumstances, use the time it takes to escort you to the door to start a brand new conversation, or bring up something that was discussed in the interview room. Keep it sharp and clean – you need to show you mean business.

Likewise, the more you relax, the less awkward you’ll be. If you want to say something a bit risque, say it in your head first, because it’s usually not worth it. Awkward people make other people feel awkward – whatever you do, keep your cool.