Sequined one-pieces. A tuxedo jacket. Jeans and a nice top. What to wear to a party is far from prescriptive. Sarah Bailey shows us how to make it new.

Like most of us, I grew up with the notion that proper, grown-up party attire boiled down to one iconic garment: The Little Black Dress (LBD). But ideas about formality and informality have shifted enormously over the years, whether you live in Manhattan, Minnesota or Montana. And, the ways we choose to socialize – myriad different parties, get-togethers and celebrations – have changed dramatically, too. So if you are deciding what to wear to a glam New Year’s Eve dinner party, a candlelit carol concert, or a chance to make like Uma Thurman and John Travolta for a night ‘out-out’ on an illuminated dance floor, the key to a perfect party repertoire is all about finding those versatile, luxe-y, modern-classic pieces – molten sequin co-ords, say, or indeed, a tuxedo suit – that you can amp up or layer, depending on how glamorous/casual/chilly the crowd or the setting. And let’s face it, we don’t always know exactly the vibe of a party until we walk through the door.

Back when I lived in New York, working on the fashion beat, and it was – quite literally – part of my job to attend parties four nights a week, I made a purchase that changed my life: a winter-white tuxedo jacket. There was an unspoken dress code that necessitated looking chic and nonchalant at the same time (just like in Succession, stuffing a pashmina into a ‘ludicrously capacious’ tote did not cut it – even in devilishly bitter temperatures). So, I learned that a flawless topper I could shoulder-drape over a cocktail dress or jumpsuit was a building block of a capsule party closet. After all, shouldn’t the special-occasion pieces we invest in be the ones that will pull out party after party, season after season? It certainly helped me maximise my miniscule Manhattan closet space and those lessons that I learned on the cocktail circuit have stayed with me.

Of course, none of this is to say that an LBD is no longer relevant. Ideally, it should be one of your easy party pieces. The modern way to wear one is to loosen up the stiffness and formality. A fluid velvet slip dress captures this season’s ’90s mood to perfection. I like the idea of layering one over a white T-shirt, or shirt, or even over black evening pants, in homage to those ’90s Peter Lindbergh black and white shoots that will forever define an era of effortless chic. And for a dressier do? Lose the shirt, drape your trusty tuxedo jacket on the shoulders and add ballet slippers or low-heeled jewelled pumps – all the better for dancing.

“Luxury must be comfortable, otherwise it is not luxury,” Coco Chanel once opined. And really, I couldn't agree more. As simple as it may sound, feeling relaxed in your skin is the magical X-factor that will ignite your party radiance – beyond any amount of brush-on bronzer or illuminating Instagram filter. If jeans are the garment that make you feel your best self, go ahead and be my guest. Obviously, this does not apply to black-tie invitations, but for more laid-back soirées, I love the sexy, rule-breaking frisson of dressing up a pair of sharp, close-fitting indigo denims with a tailored jacket, styled with a lace camisole, or a black roll neck underneath. Pair with red lipstick, shoulder-grazing earrings and voilà!– you’ll look like a French fashion editor. For country-house party invitations, say, or any event with a hint of outdoor firework watching, a heavy silk mermaid skirt and luxuriously textured oversized sweater with a metallic thread is an unbeatable combination. Top tip: a heeled boot will keep calves cozy (and hems out of the mud). Add a jewelled headband and/or drop earrings for added pizzazz but be sure to choose coordinating shades to keep your sweater/skirt combo looking considered and streamlined.

On the subject of tonal dressing, another note from my New York days – and a menswear styling trick worth stealing. One of my most stylish colleagues had a penchant for wearing head-to-toe dove gray, matching his overcoat, sweater and soft tailored wool pants. Whether arriving at a cocktail party, hailing a cab, or sweeping into his favourite downtown sushi joint, he always looked chic and put together. Finding a coat that coordinates with your outfit, that you are happy to keep perched on your shoulders until the canapés start to circulate (and the atmosphere starts to warm up), is probably the greatest party dressing hack of all. Even better, choose one roomy enough to shrug on top of your jacket without causing a sleeve-on-sleeve pile up. You won’t catch the flu if your table is parked next to a drafty exit and you can even circumvent the cloakroom queue. Ta-da! Sheer party perfection! Let the RSVPs roll…

Sarah Bailey worked at Harper’s Bazaar – on both sides of the Atlantic – for nearly a decade. A former Editor-in-Chief of Red, Porter and ELLE UK, she is currently International Editor-At-Large for Vogue Greece