It was Oscar Wilde who said that only a fool doesn’t judge people by appearances. He was right. How we look matters. In the Western world we have to wear something every day – and whatever it is, you may be sure that it tells the world something about you. It signals quicker than a lightning strike whether we are fun, clever, elegant, shy, intellectual, dowdy, sloppy, showy. You name a quality, dress can convey it.

I also believe that dressing at least moderately well is part of proper manners. Turning up in scruffy clothes to a dinner that somebody has taken trouble with is rude. It takes the shine off the evening. Wearing flip-flops to the White House, as some American teenagers famously did, speaks to me of an unattractive bolshiness.

We all know women who have turned up at work in inappropriate gear: plunging necklines, too-short skirts. It is distracting and unprofessional. But I have never understood why you can’t combine glamour with brains. The fad of some intellectuals for thinking that their IQ depends on them wearing dreary clothes seems, to me, irrational.

Glamour is a great life-enhancer, and there is no need to surrender it simply because the years are rolling by. Nor does it depend on continually buying loads of new clothes. A great haircut, fabulous shoes, cute bags and jewellery (which does not have to be expensive) can all do much to add glamour.

There is no need to copy fashion blindly, either. I’m of the view that the older you get, the more quietly you should follow fashion: follow it, of course, but at a distance. Wear diluted versions of the hot looks.

There has never been a better time for women who want to look their best. It takes a modicum of time and money – but then, doesn’t everything that is worthwhile?

How to find your own style

I can’t believe I’m quoting Paris Hilton, but she is alleged to have said: “Dress cute wherever you go. Life is too short to blend in.” She was right, too. But finding how to “dress cute” in a way that suits us isn’t easy for everybody. It may involve a bit of ruthless honesty: the first essential is a long, straight look in the mirror, deciding what is good about your body and what isn’t. Once you have worked out what needs hiding and what enhancing, you are on the way to finding a wardrobe to suit you.

I know, for instance, that, while I love plain, classy, classic clothes, they just make me look like a rather dreary librarian (I’m sure there are some very glamorous librarians, but you know what I mean). I need something a bit quirky to look interesting.

I need to hide my now-not-so-great waist, so I go for curvy jackets and dresses that have either a slightly high (empire or princess line) waist, or a low one. But I have decent legs for my size, so, even though I’m a grandmother, I can get away with shortish skirts if I wear dark tights.

Every wardrobe needs one divine dress (mine is in brilliantly cut black jersey, with long sleeves, a deep V-neck and a curving, long, quirky skirt, by the Turkish designer Ischiko) that always looks good.

When I think of my most stylish friends (most of them well past the first flush of youth), I realise that they are not the ones who take refuge in conventionally “tasteful” attire. They believe in a touch of eccentricity, but not too much.

While they always look fashionable, they are not slaves to fashion. They tend to have evolved a style that includes minimalist Japanese clothes, trousers, flattering sweaters and jackets (some of them acquired over time). They have learnt that it is better to buy one amazing piece – a jacket, say, from Miyake or Yohji Yamamoto, Chloé or Marc Jacobs that can clock up years of service – than heaps of cheaper numbers that die a quick death.

How to dress for work

Why do so many women adopt such a bland uniform for work? I understand that wearing an itsy-bitsy miniskirt and vertiginous heels is not a good idea if you’re trying to look like a safe pair of hands for a million-pound investment fund. But I can never understand why turning up in dreary clothes should be thought to add gravitas.

I’ve lost track of the number of highly paid accountants and lawyers who opt for terminally boring black, grey or navy suits. It is perfectly possible these days to dress zippily yet still look like the safe custodian of a tough criminal case or a bulging trust fund.

A working wardrobe should have lots of jackets – sharply cut, curvy, with flattering collars and necklines – to perk up classic black trousers or any number of skirts. Great shoes dress up the look of a suit no end and, even if they’re not good for buses or the Tube, what’s wrong with keeping a couple of pairs in an office drawer, or carrying them about in the oversized bags that are the current fashionable tote?

How to be glam

Never underestimate the power of glamour. Even the plainest woman can be glamorous, because glamour is quite different from beauty. It depends largely on a sense of personal style and inner confidence, which can be cultivated.

A terrific haircut is a great help. Don’t be tempted to go to cheap colourists or Tracey in the high street (unless she is extremely talented and about to be poached by Daniel Galvin). A tiny – but I mean tiny – bit of eccentricity (perhaps individuality is a better word) helps.

Well-chosen jewellery helps, too, but not too much of it: just some stunning earrings or a fantastic necklace that works with the clothes you’re wearing. For instance, I bought some amazing scarlet amber gobstoppers in Oman that look wonderful with plain black, but I wouldn’t dream of wearing them with much else (except possibly plain white linen in the summer). They would be too much. This sort of jewellery can be bought very inexpensively in the high street: just remember, don’t be timid.

How to wear black

If we are going to wear black – and we surely will, as black is the new black more often than it isn’t – we must learn how to wear it. It needs drama. It needs to be cut either limpidly in seductive chiffon or silky drapes, or shaped to follow the curves of breast and waist, or sharp and chic in the way that M. Dior did it in his last few brilliant years and Alexander McQueen does it now.

Just because it’s black doesn’t mean that it will make you feel like a million dollars, though it will make you feel thinner – a quality not to be underestimated. Here is how to do it so that the total look is rather more Catherine Deneuve than Edith Piaf:

1) Very sexy shoes: Preferably red, though I often wear some brilliant emerald-green Marc Jacobs open-toed platforms.

2) Adroitly chosen jewellery: You could do the Coco Chanel pearls number. Mlle Chanel’s were fake (of course – so much more chic, in her view). Have a huge pendant right in the middle of the neckline, or pin on a funky brooch. You should probably wear earrings to add light and “lift” the complexion. Just don’t do all of these things together.

3) Great hair: Clean, shiny, groomed, beautifully cut and tended to.

4) A cute handbag: Jewel-like, or glittery for evening.

5) Add another colour: This should be in the shape of a shirt or blouse, or scarf. Emeralds, teals and purples work well with black, as, surprisingly, does navy.

6) Some bare skin: Essential near the face. High necklines and long sleeves (especially both at once) can look too governessy.

7) Adapt your make-up: Black drains light from all but the most luminous complexions, so use a brightening moisturiser and light-reflective concealer. Sculpt cheekbones with light-reflective bronzer.

What to wear underneath

Delicious underwear is good for one’s morale.

You don’t need masses of bras. What most of us need is: one cotton bra in white; one Tactel bra in black for wearing under the tightest tops; one nude and one multistrap (for strange-shaped necklines and yokes). Then you need a divinely pretty one for those days when you never know what may happen – and two pairs of matching knickers in your preferred shape to match each bra. As for thongs, if you like wearing them, fine. I think they are awful.

When it comes to tights, it goes without saying that opaque are what you wear if your legs aren’t great. Grey with a slight sheen makes a good change from black. In summer, when opaque tights no longer cut it, take care over the precise cut-off point of the hem of your skirt. Coloured tights can work if they are carefully chosen.

What shoes to wear

Ah, shoes. I have come fully to understand the transforming power of shoes rather late in life. I discovered this by chance when I was overcome with desire for a pair of grass-green Marc Jacobs shoes. The weird thing, as I tell all my friends, is that even though they cost nearly £400, they have turned out to be a great investment, turning even the dreariest sack into something sassy and fun. I wear them with all sorts of things, and they never let me down.

So I’m now keen to pass on my new-found enthusiasm. Instead of splashing out on a new dress to give your wardrobe a bit of extra fizz, go for some glorious shoes.

How to look good

One shouldn’t confuse looking good with trying to look younger. The French seem to understand this better than we do. Women who take a modicum of trouble can look good at any age.

Skin: I don’t think there are such things as miracle creams, but I am convinced that nourishing the skin regularly keeps it softer, plumper and slows the rate at which wrinkles develop. I don’t regard the whole beauty industry as one big con – serious research goes into these creams, and cutting-edge ingredients cost more than normal ones.

Eyes: Have your brows done professionally – you can always tell a high-maintenance woman by her perfect brows. For my money, eyebrows and pedicures are the cheapest treatments that really do make an impact.

Hair:If you see someone with a cut (or a colour) that you admire, ask who did it. Then go for it. Don’t hang on to long tresses because once, long ago, someone admired them: nothing is more ageing. If you spend money on nothing else, spend it on your hair.

— Things I Wish My Mother Had Told Me by Lucia van der Post is published on November 1 by John Murray for £16.99. It is available for £15.29 from Times BooksFirst (p&p incl), 0870 1608080

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