But there's a lot more to dressing for success these days. Executive coaches such as Eleri Sampson of Positive Images, who has advised more than 100 organisations including BT, Morgan Stanley, the NHS and Royal Mail, work on a holistic approach that encompasses not only the clothes you wear but the body language you use.
Going to meet Ms Sampson was the most traumatic bit. Not wanting to turn up as a candidate for Worst Dressed Woman of the Year, even underwear took a whole 10 minutes longer than normal to choose. I formulated apologies for my root growth on the way and imagined her sighing inwardly at the struggle ahead.
Nothing like that at all. All she asked was why I wanted to change my image (reminding me of the old joke about how many psychiatrists it takes to change a light bulb - one, but the light bulb has to really, really want to change). "So what is the most important quality you need to get over in your job as a journalist?" she asked. "Trust," I replied, trying to look her straight in the eye. Unsure how this would translate in a world of neck scarves, I added efficiency and creativity for good measure.
"I'm not a navy suits kind of girl," I said nervously.
"I can see that," Ms Sampson replied. "But we might be able to get you into a navy suit with a twist. I can't wave a magic wand. But I can try to capture the essence of who you are and how you want others to see you. The next step is to look at your aspirations, where you want to be going, your role model. Although by the time you reach me you'll have already done quite a lot of thinking. Now it's time for some action."
And this is what she proceeded to ask: who was I, where did I want to go, who was my role model? I found it quite difficult to reveal this to someone I had just met, knowing she'd try to change me on the outside. "The reason clients come to me is because they want to create more impact," said Ms Sampson. "But at the same time they say, `I want to be me.' My role is to make the changes, particularly your changes in attitudes, visible, to help my clients create the appropriate image."
In fact, the first thing to realise was what was appropriate, she said - however tempting it might be to go out on a limb. "For somewhere, say, like Morgan Stanley or another investment bank, there is undoubtedly a team strip and you would be a fool not to find out what it is." The exception would be if you were outstanding at your job, and even then you would have to keep performing at incredibly high levels. Otherwise it's back to the navy suit.
A lot of clients come to Ms Sampson with their own clothes and she helps them to decide what could be added or subtracted to enhance their image. "I really have to be tactful, but I do have to be straight with them as well," she said. "I end up saying things like, `Do you think what you're wearing reflects the image you want to project?' " Other people, she says, "just lie back and say `whatever you think'. But I need something to get started with."
Personal consultation does not come cheap - preparation for an interview with Ms Sampson begins at pounds 300 and the whole package can reach as much as pounds 1,500. But I defy any woman not to enjoy someone devoting two hours to making her look better - it's the most fun I've had in ages. Ms Sampson created two looks for me: one for everyday work, and a more formal look for an interview. The first - a rust jacket and navy trousers - was similar to what I might have chosen myself, but the added extras made it. The square jacket was the wrong shape for me, but by carefully hitching up the sleeves and securing them with armbands, the look was transformed. Added to that was a pair of gold earrings, a handbag and shoes with a modest heel.
But this was nothing to the strict body-language coaching that followed. Ms Sampson made me practise coming into a room more times than a Lucie Clayton graduate. Breathe deeply first, so that you are relaxed and your shoulders are down, she instructed; smile, maintain eye contact, and, crucially, pause "for the count of one or two if you can bear it". "No Hollywood actress worth her salt would mess up her entrance," said Ms Sampson. And she's right. As silly and self-conscious as I felt doing it the first time, by about the seventh I felt - and looked - more confident.
On to my "interview look". I allowed myself to be coaxed into my bete noire - a navy suit with matching court shoes. Again, with a few judicious twists - both long and short skirts, a silver torq, hair swept off the face and an accompanying handbag - I could see myself as the efficient professional. But Ms Sampson warned she could not perform miracles.
"People seem to think there is such a thing as a perfect candidate and if they pay me enough I can make them look like it," she said. "I can only make them look appropriate - and, even if there were such a look, it would be a waste of time hiring the `perfect candidate' who couldn't do the job."
However, there are some general rules. For an interview, wear neutral colours with perhaps a coloured jacket but not a coloured skirt; no patterns (people can take against them); no perfume (ditto); play it safe in classic cuts; no boots, sandals or high heels; never anything that displays a lot of flesh; and nothing "cute", such as a necklace with your name on.
For men, a close shave is a must, short shirt sleeves should be avoided and a tie should be "interesting but not amusing". Socks should be knee- length (covering hairy legs). Ms Sampson winces at the memory of a man who wore Mr Happy socks.
As for body language, she suggests interviewees remember "whoopsie", which stands for Walk like a winner; Hands under control, OO for eye contact, Pause for Impact, Smile, Intellect - remember your brain, and Engage with the person who is conducting the interview.
If all that was too much, Ms Sampson said, no one can better the warning given by Beau Brummell, the Regency dandy known for his quiet elegance: "If someone turns to notice you in the street you are either wearing something which is too new, too fashionable or too tight"n
Eleri Sampson will be at the Diamond Executive Coaching Stand at the Personal Development Show, 27-29 June at Olympia in London.