I know what you’re thinking: you wouldn’t dress like this if I paid you. Your dad’s 80s blazer, over a white lace nightie, with an upturned fruit basket on your head, punk choker and square sunglasses, a la Gucci? Er, I don’t think so. A cartoon-print Crombie coat with knee-high sport socks and winklepickers? Not today, thanks all the same, even if it is Prada.

Don’t take this the wrong way, but you’re mistaken. You will dress like this. Not necessarily this week, or even this year, and not, I admit, exactly like this, because you would be bankrupt, and people would cross the street to avoid you. But still. The clothes you see here from Milan fashion week will have a huge effect on what all of us wear.

There is an often-repeated line about how Donald Trump shouldn’t be taken literally but should be taken seriously. That, basically, is the best way to think about Milan fashion week. In other words: scoff at your peril, because this is real life. What happens on the catwalk is exaggerated and skewed for effect, but it still directs what we all wear.

There is a knack to translating catwalk into clothes. First, don’t let the glitz and glamour distract you from the real story. You know how Agatha Christie set her whodunnits in exotic locations – the Orient Express, a Caribbean beach house, an archaelogical dig in the Middle East – in order to keep the reader from too swiftly identifying the bones of the plot? Miuccia Prada, Donatella Versace, Domenico Dolce and Stefano Gabbana do pretty much the exact same thing at Milan fashion week, sprinkling supermodels (Versace), sequins (Dolce & Gabbana) and lofty, backstage-TED-talk pronouncements about womankind (Prada) over the catwalks like so much dry ice, so that we are caught up in the narrative and forget that we are being sold clothes. And – remember the suspicious-sounding Mr Owen in And Then There Were None, who you think is the murderer but turns out to be just a pseudonym? – designers then throw red herrings into the mix. Racy slogans, Gigi’s abs, tiaras, fake-fur bum bags. All just misdirection.

To understand what’s really going on, make like an X-ray machine, and zero in on the silhouette. Are the clothes tight, or loose? Where does the hemline fall? Where can you see skin? What is happening at the neckline: is it one clean layer, or are there multiple collars? Are the lines angular or soft? Next, look for the pieces that link different looks together. Is there one garment that keeps reappearing? A colour, mood or decade that threads through different designers’ shows? These are the clues that will help you make sense of the catwalk. Spoiler alert: I’ve gone ahead and cracked the codes for Milan fashion week.

Sheer party dresses at Dolce & Gabbana. Photograph: Estrop/Getty Images

▲ Dolce & Gabbana means that party dresses are going see-through

Don’t be fooled by all the cardigans at Gucci. Milan fashion week is never not about how to be sexy. Last season, the hotness was all in the ab gap. The wearing of an abbreviated top to display a slice of ab the height of a tequila shot above the waistband of your jeans or leggings, seen on every pavement this summer, was a look that came from these very catwalks a year ago. The new way to be sexy, as seen in Milan, is with a sheer skirt over visible big pants. This was seen at Roberto Cavalli and Fendi, as well as Dolce. For the non-Hadids among us, this is likely to translate into party skirts and dresses that have an opaque petticoat to the upper thigh, and a longer sheer layer over the top.

A new collar situation at Prada. Photograph: Maestri/WWD/REX/Shutterstock

▲ Prada means that the polo neck is on the way out

What goes on just under your chin is the headline of your outfit. This isn’t a fashion fact, it’s a fact-fact: think ties, football scarves, Theresa May’s strong and stable necklaces. So even though Miuccia Prada said backstage after her latest show that the collection was a celebration of the female gaze and a call to the sisterhood to embrace direct action, I would argue that it was actually about a new collar situation incoming on the fashion horizon. The default catwalk neckline for the past year has been a polo neck under a slip dress or a coat. Here, by contrast, most outfits featured two sharp-collared crew-neck tops, one on top of the other: a shirt with a collared coat, as here, or a shirt under a boxy jacket. This catwalk is especially significant because the Prada and Miu Miu catwalks were instrumental in making the poloneck-under-everything trend happen, but the look happened at lots of places: at Jil Sander, where it was a white shirt under a black jacket, and at Bottega Veneta, where a coloured silk blouse was buttoned under a contrasting jacket.

Checked blazers at Gucci. Photograph: Pixelformu/SIPA/REX/Shutterstock

▲ Gucci means the check blazer now goes over everything

Eleven models on the Gucci catwalk wore checked blazers. Now, I don’t know how closely you watched the Gucci show, but you could have missed this even if you were there. Because one checked blazer was worn over a full-length white lace gown, with a straw spaceship hat; another over a Gucci-monogrammed skirt with polka-dot nude hosiery, high-heeled sandals, smudged orange lipstick and a fringe that is best described as “Farrah Fawcett sticks her hand in a plug socket”. Smoke and mirrors, see! Because the most significant takeaway from Gucci this season is not the Elton John tracksuit, but the checked blazer, which is already a front-row and streetstyle favourite this fashion month, and is hereby confirmed as a key look for next season, too.

High-waisted vamp jeans at Versace. Photograph: Estrop/Getty Images

▲ Versace means the vamp jean is the new mom jean

It was difficult even for hardbitten, jaded front-rowers such as myself to concentrate on the catwalk when there was Actual Cindy and Actual Helena to look at, but the legacy of Versace’s new collection goes beyond reigniting our fangirling of the original supers. A high-waisted jean – one that emphasises the shape of the waist and hips rather than hiding them, as skinny jeans do – has been the hipster denim look for a while, but in its ironic mom-jean guise it had limited mainstream cut-through. The new vamp jean is high-waisted, but unashamedly sexy rather than knowingly quirky. It came in baroque prints, in black leather and in pastel on the Versace catwalk. In blue denim, it is coming your way soon.

The return of the pencil skirt at Fendi. Photograph: Victor Boyko/Getty Images

▲ Fendi means that the pencil skirt is back

We had the full-volume midi skirt; then we had the fluid, soft-power midi skirt. For next season, we have the long pencil skirt. Fendi is a catwalk that sets trends (the mastermind is none other than fashion rock-god Karl Lagerfeld) and for next summer, the label brought back the long, straight skirt. A lightweight top tucked into a stiff pencil skirt – some here were black leather, some were boldly chevron-striped – was a new silhouette for next summer. Note also that the same shape happened at Gucci. Whether you go the Full Milan and pair the skirt with a sock and a sandal is at your discretion.

Pencil-sharp flats at Roberto Cavalli. Photograph: Estrop/Getty Images

▲ Roberto Cavalli means that the pointy pump is the new loafer

The fashionable flat shoe is a very important wardrobe category. Do you want to pull off that “I don’t try too hard, I’m just naturally this fabulous” look – you don’t need to answer that, it’s a rhetorical question, duh – then in that case, you need the right flat shoe. That has been, at various times over the past four years, a furry-lined slide, a classic loafer and a simple minimalist white trainer. For next season, it will be a pump cut low at the sides but whittled to a pencil-sharp point. I would suggest you take note.