Avery Dennison Office Products believe image is everything and has commissioned psychologist Donna Dawson to study how the image we portray can affect our success at work

It may seem shallow, but appearances count. You know the saying about only having one chance to make a first impression, well it's true. And if you want to be taken seriously by your colleagues at work, you're going to have to dress to impress.

The fast track to promotion

Whether you work in a High Street bank, a city corporation or a trendy ad agency, every organisation has its own dress code, whether it's detailed in a company handbook or left unspoken. And if you want to succeed within your organisation, the first thing you have to do is to dress to look like you fit in.

'But I'm an individual', you cry. Save it for the weekend! When you flout the rules, it will cost you. Whether you dress more formally, scruffily or sexily than your peers, your appearance speaks volumes. And the message is: I'm a rebel with little regard for my company's image.

'These individuals may be tolerated if they are productive,' says Donna. 'But the management may conclude that they are undeserving of the opportunities or promotions that their talents actually deserve.' Employees who meet the dress code to the highest standard while still finding a way to express themselves as individuals may find that their weaknesses are unnoticed. 'The right image can give them quicker access to the top of the corporate ladder,' says Donna.

Clothes to boost your productivity

Whatever the dress code, it is essential to feel 'right' in what you wear. Think first about what the day has in store for you. Do you work behind the scenes or meeting the public? Then consider the physical activities you will need to undertake to complete the day's 'To Do' list.

If charged with a huge mail-out, jeans could well be the order of the day, but skinny-cut trousers are going to restrict movement and feel uncomfortable if you are sitting for long periods of time. Similarly, you may want to avoid this season's short, 1960s-inspired A-line dresses if you have a day of filing ahead of you, to spare your colleagues' blushes!

The ideal wardrobe choice should be something that you can put on and forget about, without having to tug at hems or rearrange necklines. Moreover, it should make you feel good about yourself. When self-esteem is high, your energy levels are increased and you become more productive.

Fashion forward thinking

If you get a buzz out of fashion, it might be appropriate to wear elements of a new trend to work. It shows openness and awareness of what's in vogue! Naturally, not all trends are work-appropriate, but the return of the narrow-cut jacket this spring is perfect for most work environments, whether teamed casually with jeans or worn in a more traditional style.

Key accessories for the ambitious worker

If you want to add personality to your working wardrobe, do it through accessories. A comedy tie or fun earrings? Maybe not. This summer, fashion pundits say it's all about the right shoes and bag. Spend as much as you can afford and watch as colleagues clock your fashion sense and silently swoon over your new purchases.

Dress for success: a black & white issue?

Think about the colours you wear too. Psychologist Max Luscher, who carried out extensive testing on colour and personality, discovered that every colour affects us physiologically. 'When we see or wear a colour, its vibrations affect our brainwaves and nervous system. With this in mind, you can create a more positive impression of yourself in the workplace, by adding the appropriate colour,' says Donna.

• Black and white are the big colours for Spring/Summer 2007 and they're perfect for work, suggesting dignity and honesty respectively
• Nudes, pinks and anything that smacks of the boudoir should stay there
• If your working environment is a little too political for comfort, wear green, the colour of balance
• If you need to spur your colleagues into action, red will not only raise everyone's heartbeat and make you feel more energetic, you'll project a sense of urgency to those around you too
• If everyone's panicking, wear blue, a cool colour that lowers both the breathing and the heart rates
• Grey, another key colour for this season, suggests you are calm, dedicated and self-possessed
• Chocolate brown has a similar gravitas to black or navy, suggesting you are hard-working and dependable, but approachable

So, be careful next time you're rummaging through your wardrobe, hoping for something to 'speak' to you. It might just be saying more than you thought!