Lesson three, keep an eye out for interesting fabrics (from herringbone to satin) and be ruthless about details. Sure, jewellery, tassels, fringes and feathers up the ante, but unless you’re meticulous about their quality and controlled about the amount of colour you’re piling on, it can all start to look like fancy dress. Lesson four, monochrome doesn’t have to mean black and white. It could be navy and grey or camel and orange… anything that imposes an orderly boundary on the limitless and sometimes overwhelming choices out there. And you can build in light and colour via a clear bright lipstick (Sisley’s range of 12 Phyto Rouge Shine lipsticks deliver moisture and an energising but not overpowering hit of colour (£40, sisley-paris.com), while Glossier’s Ultralip is an excellent budget version at £14 (glossier.com) and dark green or blue eyeliner, which won’t register as stagey, but simply bring out the colour of your eyes. I find using powder and an eyeliner brush not just easier to apply than liquid versions, but the results are more subtle and flattering as you get older. I really like the range of colours in Victoria Beckham’s vegan palettes and find they last a long time (£50, victoriabeckham.com).

Lesson five – show some skin – stems from Mair’s assertion that “a restricted palette is such an easy way to look pulled together. It never feels too much, even if you’re mixing up print”. She’s absolutely right. It also allows for a degree of cleavage and bared shoulders, à la Laetitia Casta, on the Ralph Lauren catwalk last week, without any danger of looking vulgar. An off the shoulder top or dress is an ageless, glamorous dress-up piece that looks good on everyone.   

Keep patterns classic (lesson six), whether that’s a herringbone tweed or a Shetland knit. If you want a sublime example of this, Uma Thurman’s black satin, Bottega Veneta fishtail skirt and white shirt at the Oscars on Sunday was a salutary lesson in how the right kind of minimalism can hold its own in the face of what might, on paper, seem like superior displays of firepower.

Final lesson: just because something’s classed as a staple, it doesn’t mean you shouldn’t invest in the best version you can afford. Once you get past the basic-item-basic-price mindset, they become one of those magical wardrobe fixers you can wear anywhere while still looking and feeling like you. A white shirt is best when it’s slightly oversized, and in a full-bodied fabric that holds its shape, or in a floppy, thick linen that drapes gracefully. Arket and Cos are good high street sources. If your budget allows, Joseph’s silk crepe shirts (joseph-fashion.com) and Emma Willis’s Made-in-England, Swiss cotton shirts (emmawillis.com) are worth every penny, improve with wear and will never clog your wardrobe with their frivolity.