WHEN Julia Roberts played Erin Brockovich in the film of the same name, she dressed like trailer-park trash and the character still made a rollicking success of her career. Real life is different from the movies and skimpy, tight-fitting clothes are not much help to anybody wanting to climb the ladder of success.

Never underestimate the importance of what you wear to work. “Human beings are incredibly visual animals,” said Rowan Manahan, the managing director of Fortify Services and author of career management guide Where’s My Oasis? “We take an immense amount of meaning from non-verbal cues such as body language, tone of voice and what you happen to be wearing. These govern people’s impression of you.”

This is particularly true in the case of a job interview when the impression you make in the first few seconds can be a critical factor.

“Dress as you would expect to dress if you had the job,” said Terry Prone, the managing director of Carr Communications. “Do this within limitations, obviously.”

How do you know you have hit the right note in terms of your appearance at an interview? Manahan offers two rules of thumb for this situation: be one of the best-dressed people in the room and look like a newsreader.

Dressing well at an interview might help to clinch that corporate role but pay rises, promotions and other career successes may be slow in coming if you don’t keep up the standard while in the job.

“At some stage in every career, decisions are made about you,” said Manahan. “Will they keep you or let you go? Will they promote you or leave you where you are? These decisions are being made behind closed doors so what you have to do consistently is to have the game face out — that extends from the Hermès tie outwards.”

Darker colours tend to be more appropriate at work although there is no harm in adding a splash of brighter colour with accessories. Just don’t go overboard.

Prone says Carr Communications has a rule. Don’t wear anything louder than you are.

“Your clothing should be a background to your personality and performance, it should not take over from either,” she said.

There is always an exception, says John Keogan, the director of outplacement services at DBM Ireland. “I remember a client who was going for a job in a children’s environment,” he said. “That is one case where dressing brightly made a difference. She wore bright colours and made a huge impact on the children, which helped her to get the job.”

Prone’s firm has another rule particularly for men: the two Ps and a P rule.

This means they can wear two plains and a pattern or two patterns and a plain.

“If you have a check shirt and a stripy tie,” said Prone, “you should wear a solid colour suit, because otherwise you’ll amount to a visual distraction. Or you can wear a plain shirt and suit and a patterned tie.”

If a job involves operating in different environments with different people, you may need to modify your wardrobe accordingly. Manahan wears high-end suits when he is with corporate clients but dresses more casually in his own office.

“On my own ground, when people are coming to me for career advice, I deliberately don’t wear corporate wear because the last person my client saw in such clothing was the person saying they were out of a job,” he said.

When it comes to the relaxation of dress codes on a Friday, as happens in many offices, casual is a relative term.

“If you turn up on the casual day in torn jeans and a Nirvana T-shirt when your colleague shows up looking like Gwyneth Paltrow in The Talented Mr Ripley, who is the boss going to take more seriously?” asked Manahan. A more measured approach is needed.

Don’t be afraid to seek advice on appropriate wear when at an interview. “Ask about the dress code,” said Keogan. “If you don’t feel comfortable wearing a suit every day or you are uncomfortable having to ‘power dress’, you don’t have to take the job.”

Once you know what is expected, go shopping but take somebody you trust with you. An ill-fitting suit in the wrong colour for you will do no favours even if it is the most expensive in the store.

Not only will dressing well create a good impression, it’s also respectful of your colleagues, says Prone, and it will help your own confidence. “General Patton insisted that all his guys wore ties at all times and were polished to within an inch of their lives,” said Prone. “Not because of how it made them look but because of how it made them feel. Being forced to dress ‘properly’ every day tended to raise morale and a sense of team-building.”

Times Recommends

• Blackstone target at $7.75bn on China deal
• An opportunity in the Muslim community
• BSkyB deal may spell trouble for Virgin