Kate Middleton's biggest style lessons

The Duchess of Cambridge tries trends on her own terms. Photo / Getty Images

As The Duchess of Cambridge prepares to celebrate her 35th birthday, we look back at the 35 style lessons which she's mastered- some of them universally useful...

1. You need to know when to let something go (no matter how much you've loved it )

A few years ago, the Duchess was often spotted in her beloved Aquaitalia ankle and knee boots but after being well-loved they soon began to look a little tired and scuffed. Sensibly, they've been done away with in favour of shinier styles.

2. Beware of flying hemlines...

Putting small tailors' weights in the hems of one's skirts is a fashion trick that the Queen has been practicing for years. But it was a lesson that the Duchess almost learned the hard way, when her flyaway chiffon dress by Jenny Packham almost blew up in front of photographers on a windy Calgary airfield in July 2011.

3. Like something that isn't quite you? Tweak it

When Kate embarked on the royal tour of India last April, she wanted to honour Indian designers and traditional dress codes, whilst staying true to her own sense of style. She and her stylist Natasha Archer adapted a catwalk look from Lakme Fashion Week by Anita Dongre, turning the stole and full-length tunic into a midi dress with a belt. "It looks easy, breezy and so contemporary," Dongre told us at the time.

4. A little 'glow' will do wonders for your whole look

The Duchess's complexion has become subtly more polished and 'glowing' over the past few years. Kate's radiant skin could be down to the Biotulin Supreme Gel that she recommended to Michelle Obama, which is dubbed as 'Botox in a bottle' while it has been long-rumoured that her favourite facialist is Deborah Mitchell who is known to for tricks which make skin look younger and smoother. How does this impact her style? Well it means that every time she steps out, she looks that little bit more sleek and pulled-together, no matter what she's wearing.

5. Online shopping is a Godsend

The Duchess has cottoned onto the joys of clicking from one's sofa- or, more likely, getting Archer to do so on her behalf. She recently wore a jumper by Iris and Ink, the in-house label by The Outnet but it's thought that many of her new pieces are also the result of online hauls.

6. ...But nothing beats a browse in the shops from time to time too

Until a few years ago, the quintessential Kate picture involved her on a King's Road jaunt, often with Carole or Pippa, perusing the wares in the Whistles, Zara and Peter Jones. With two toddlers and an ever more demanding public role, there's less time for that sort of thing now, but we do know that she popped into Fenwick to buy the red version of her favourite Preen dress.

7. You can never have too many coats

Scour through the Duchess's every look and one thing becomes increasingly clear; she is not one to subscribe to the school of thought that one needs only six coats. In bleak British winters, statement toppers are what makes an outfit, be it a bold fuschia Mulberry, a neat baby blue McQueen, a boucle tweed by Erdem or a trench style by Hobbs, the list could go on and on and on.

In bleak British winters, statement toppers are what makes an outfit. Photo / Getty Images

8. Share stuff with your sister, mum and Grandmother-in-law

It might be a niche example of the common practice of sharing your relatives' stuff, but Kate made headlines earlier this year when she wore a set of pearl earrings owned by The Queen to view Vermeer's Girl with a Pearl Earring during a visit to The Hague. She often borrows pieces from Her Majesty's collection but more relatable for the rest of us is the fact that Kate is known to swap clothes with her mum and sister; the Duchess wore a £139 Reiss dress which Carole had worn two years earlier in 2012 while some Kate-watchers are speculating that the scarf Pippa wore to church on Christmas morning was first seen on her big sister in 2006.

9. If you love it, buy two

While we'd never be ones to discourage experimentation, there's something very grown-up about knowing what suits you and sticking to it. Kate portrayed excellence in this category when she picked up the black version of the red Preen dress she wore in Canada earlier this year. Earlier the same day, she had shown that her penchant for L.K Bennett's sophisticated day dresses is a considered motive, wearing a similar style to one she first wore to greet the Obamas earlier this year.

10. Sometimes a girl and her skinny jeans just cannot be parted

Fashion moved on from skinny-jean mania long ago (it's all about flared cut-offs or rigid vintage cuts now) but Kate has shown herself to be a steadfast fan of her skintight J.Brand and Zara favourites. Although the shoot she did for Vogue's centenary issue did coax her into dungarees, Kate is still favouring skinnies off-duty and for more informal engagements.

Kate has remained faithful to her beloved skinny jeans. Photo / Getty Images

11. ...And it's much the same with Breton tops

Many fashion commentators probably harbour a secret wish to see the Duchess out of her skinny jeans but the same could never be said for the striped tops by the likes of Me and Em and Petit Bateau which she is regularly spotted in; it is a truth universally acknowledged that noone can ever speak ill of a classic mariniere.

12. Hairnets and Alice bands can, admittedly, be useful tools

The Duchess caused much debate when she was spotted wearing a tortoiseshell Alice band earlier this summer while others noted that some of her sleekest updos were being kept in place by a good old-fashioned hairnet. They may not be the most glamorous of accoutrements, but Kate is clearly savvy to their timeless ability to keep unruly hair in order- top of the priority list when your image will be seen across the world.

13. Build a staple arsenal of accessories

Boxy clutch bags, plain pointed suede pumps, knee-high boots, elaborate millinery... it's the finishing touches which so often bring a look together.

14. ...But there are other shoes apart from nude courts

This is a learning which it appears Kate is only on the very cusp of learning but lately there seem to have been fewer sightings of her wearing the L.K Bennett patent nudes for which she became renowned. Far chicer are the tasselled Tod's heels, scarlet Gianvito Rossi and J.Crew block heels which she's been seen in over the past few months.

15. Want to up your style game? Get someone to shop on your behalf

There's been a marked sleekification of Kate's wardrobe over the past year or so- gone is anything scuffed or a bit unfitted, replaced by flattering cuts and more designer names. The woman to thank? P.A-turned-stylist Natasha Archer who has taken on the task of upgrading both William's and Kate's wardrobes.

16. Fashion is a diplomatic device to be employed liberally

For most of us, diplomatic dressing is limited to buying a souvenir scarf when we go on holiday but an unspoken aspect of Kate's role is soft diplomacy, which means flattering hosts with outfits which nod to their culture. Whether it's wearing local designers (such as the traditional Bhutanese skirt woven by local artisans) or clever colours- see the red and white Alexander McQueen dress chosen for day 1 of the royal tour to Canada- this is a lesson which Kate could teach to degree level by now.

17. Pick the trends which work for you (and ditch the rest)

By 35, no-one should be thinking that being a slave to trends is a good look and Kate has worked out exactly how it's done. Although she's trialled some very of-the-moment looks, the Duchess never looks like a fashion victim. The cold shoulder trend was a triumph for a couple of evening looks earlier this summer while a pie-crust collar was a sweet choice for a children's tea party. But something tells us we won't see Kate in vinyl trousers or a giant puffa jacket.

Kate showed her fashion nous in this off the shoulder dress. Photo / Mark Mitchell

18. Wherever possible, shop designer

The Duchess has long been lauded for the high/low mix of her wardrobe. But when you're fabulously wealthy with the eyes of the world on your every public appearance, Kate has realised that very often only the bespoke proportions and superior fabrics of designers buys will do.

19. When it come to jewellery, affordable can be just as stunning as precious pieces

Bling is an essential component of any glamorous ensemble but Kate's modern attitude has paid off in this department, with Zara statement necklaces often proving just as dazzling as royal heirlooms.

20. ... But every woman needs to have a few classics

Namely a Ballon Bleu de Cartier which was an anniversary gift from Prince William in 2014.

21. Err on the right side of matching your children

The Duchess has avoided going full-on matchy-matchy with George and Charlotte but the Cambridge family are never knowingly un-coordinated- usually all dressed in a tonal palette of blues, reds and creams.

The Royal family chose to all wear red for Christmas. Photo / AO

22. Ignore your husband's fashion put-downs

William once said that the bright yellow Roksanda dress his wife was wearing to take her first steps on Australian soil was like a 'banana'. Witty, sure, but quite rightly it didn't put her off wearing it again at Wimbledon this year.

23. A belt can transform an outfit

Trace the Duchess's style evolution over the past five years and there's a subtle but significant constant- a waist-cinching belt. She often chooses one to add extra definition to straight cut coats or add extra dazzle to evening looks.

24. Pick your moments to prove your Princess credentials

Another one which is more about status than age, but over the years Kate has settled into her royal role- and all that will entail in the future- gradually upgrading her look to reflect it. Of course, tiara and ballgown moments are a natural occasion to up the ante but the increased confidence was evident in the difference between what Kate wore to leave hospital with her two babies; with Prince George it was all soft curls, comfy wedges and a loose comfy dress. A couple of years later, Princess Charlotte's first taste of public life had her mother wearing proper heels and a white dress mere hours after giving birth. A move which seemed to put her on another plane of reality.

25. Don't be afraid of colour

Red, brown, fuschia , grass green, cobalt blue, blush, yellow, beige, turquoise, cream, navy, aubergine... The duchess has tried them all.

She often chooses one to add extra definition to straight cut coats or add extra dazzle to evening looks. Photo / Supplied

26. Longer lengths are much more chic than above-the-knee

If you have great legs, logic goes that you should them off. Its a sensible approach which Kate long bought into but that's started to alter with sophisticated below-the-knee styles making up the majority of her looks.

27. A black polo neck will bring any outfit together

As the Duchess demonstrated on Christmas day, every woman would do well to have a few turtleneck knits in her wardrobe; paired with a skirt and heels they make a quick, effortless and elegant outfit- also great underneath her beloved coats.

28. Be brave about departing from your comfort zone

Kate has been famed for her love of particular labels over the years; she practically made Issa a household name, she was never out of Reiss in the early months of her marriage while Alexander McQueen and Jenny Packham have become her most trusted designers. And yet, she's had many a wardrobe hit with new labels she's introduced, from the perfectly festive Vanessa Seward dress she wore in December to her recent discovery of Preen's great eveningwear.

29. High street and designer can work in the same outfit

A Dolce and Gabbana dress paired with a Zara jacket was a spot-on example of this.

30. No matter how gloriously glossy your hair, an updo is often the most elegant option

When wind, humidity or rain are threatened, the Duchess's hairdresser Amanda Cook-Tucker is always on hand to get her natural curls under control- always with faultless results.

31. Look to timeless fashion icons for inspiration

There was something very Jackie Kennedy about the prim and polished skirt suit which Kate chose for a recent visit to Holland, a meeting which was said to indicate her becoming a 'potent force' in bridge-building with other European countries in the wake of Brexit.

Then there have also been countless comparisons with Princess Diana...

What does this mean? That even if you sometimes feel stuck for inspiration, there really is no shame in looking to the women who have done it brilliantly in the past- and that counts whether you're dressing for a royal tour or a drink at the pub.

32. A great blazer can immediately upgrade a look

Kate's favourite style is by Canadian tailoring label Smythe which she has worn countless times to smarten up those beloved skinny jeans or as an extra layer over a dress.

The Duchess relies on jackets from Smythe. Photo / Getty Images

33. Have conviction with your personal style

When the duchess agreed to pose for Vogue's centenary cover, she did so on the proviso that this wouldn't be like many royal shoots of the past. "She didn't want to be dressed as a fashion plate and was not keen to be shot in gala gowns and tiaras," wrote Vogue editor Alexandra Shulman. Relaxed country might not be a revolutionary look, but it's what Kate feels comfortable in.

34. Don't be afraid to leave a few details to the last minute

When Kate was in Canada, she purchased a pair of earrings while in Yukon which she then wore the very next day.

35. When you know you've nailed it, there's no time wasted looking in mirrors

Now that Kate has sorted and sussed all of the above, there's little need for over-examination. Shulman also explains that despite it being her first magazine shoot, the Duchess "scarcely" checked herself in the mirror and expressed no concerns about her appearance.

This article was originally published by The Telegraph.