For most men, the most flattering shorts length is from mid-thigh to just above the knee, depending on your height (cropped higher for shorter men). Of course, there are exceptions. If you’re buff like Matt Damon in Christopher Nolan’s upcoming The Odyssey and you have quads like lamb shanks, hike ’em up and show them off. Otherwise, a brief length looks like you’re trying too hard, while shuffling along in a pair below the knee looks like you are not trying at all.

The leg should boast a slim fit. Choose a lightweight fabric, such as a cotton twill or cotton-twill blend. The shorts should be flat front and curve around your butt, so stiffer fabrics such as Japanese denim are going to flatten your behind and it is vital for your ego you don’t walk around looking like gravity has won.

And unless you are on a real safari and need the pockets for ammo, K-rations and a walkie-talkie, you don’t need cargo pants. They flatter no one, regardless of age.

Wear whichever colour flatters your tanned torso or enhances your eyes. You can’t own too many. Polos are nearly foolproof and take up no room in a weekend bag. However, note that it’s not uncommon for men over 50 to experience a more noticeable nipple-areolar complex. For some reason, this condition always appears more prominent when the polo is white. If you are determined to wear white, try to find where your wife keeps her nipple tape.

Do you really need a summer sport jacket? Yes, you do. You’ll see. Something will come up that will require a stylish ensemble. A work lunch, a fundraising gala, a summer wedding, dinner at someone’s country house. A sport jacket never fails. And the great thing is it can be the easiest grab-and-go item to elevate whatever you already have on.

Don’t think of it as just a blazer. With its lightweight, unstructured, unpadded, slightly cropped and often unlined construction – the first four are prerequisites – the jacket can wind up a savvy substitute for a windbreaker. It provides an instant upgrade to any simple daytime summer outfit, even when worn over a T-shirt.

Linen is a good option. However, like many Americans, I have a problem with linen wrinkling as easily as aluminium foil. It makes me want to carry a battery-operated steamer in my bag. Europeans tend to handle wrinkled linen with more aplomb. However, it’s easy to find linen jackets blended with cotton, rayon, viscose, bamboo, or silk that will help reduce this issue. My preferred fabric is cotton; I like the feel of it better.

The most versatile shades are ivory, stone, khaki or indigo. A bold colour will get you noticed but it will cut down how often you’ll reach for it. Patterns are “cute”. My belief is that, at your age, if someone says what you have on is cute, you should reply “thank you” and when you get home, burn it.

I would love to declare 18 February, the birthday of Joseph Haspel Sr, an international day of mourning. Haspel designed the first seersucker suit in New Orleans in 1909. It’s such an unappealing fabric to the touch, and even if you think seersucker feels cool, you look as if the rest of the quartet went ahead without you because you lost your straw boater or forgot the words to “Sweet Adeline”. Please don’t.

Regardless of your weight, size, age or shape, nothing beats white jeans in the summer. They get dirty fast, of course, so buy a few pairs. However, during the apex of a heat wave, even white jeans can feel like unwanted second skin. In such situations, flat-front, mid-rise, tapered cotton, cotton-linen or tropical wool trousers are not only comfortable, they are also an easy upgrade when paired with nothing more complicated that a T-shirt. Any colour works, but sherbet shades are a fun seasonal option without being as conspicuous as a red blazer.

Trousers with anthropomorphic patterns pop up way too often around country clubs and summer parties with elderflower cocktails and cucumber sandwiches. Some grown men think they’re both bold and adorable. They are not. Unless you can carry off a cascade of pigs, zebras, giraffes or sharks trailing down your legs with an insouciant sense of youthful irony, you will look as stylish in a plaid clip-on bow tie worn with a shawl-collared tux. And you will never get laid while wearing them. You have my word.

Summer knits can look elegant and feel so sensually gratifying, especially when you have a touch of a tan. But select your knitwear carefully. You want weaves that are open, though how much so depends on how confident you feel about your body. The sweater should drape, not hang and move with you, nor should it cling to your skin. Necklines should be open, round necks should be wider than a crew neck, while V-necks may sit slightly deeper – and consider boat-neck styles.

Some weaves to look for include pointelle knits, ramie – which has a subtly notable shine to it – crochet, fine-gauge merino wool and, of course, cotton and cotton-linen. Avoid tight knit construction and any fabrication with more than two per cent stretch or synthetic content. There are way too many cashmere sweaters masquerading as summer weight. If they are heavier than a croissant, avoid them.

As for that Hamptons staple of wearing a pastel cashmere crew neck causally draped around your shoulders – often with those anthropomorphic pants – why don’t you go all out and just wear a mink stole? I’m kidding. But it comes across as pretentious. Either wear the sweater or leave it in the car in case you “catch a chill” later.

The right shoe will instantly raise the level of sophistication of your outfit – suede shoes, a Venetian loafer, a woven leather slip-on. In other words, shoes without height atop a thin leather sole in light colours or nubuck effortlessly radiate refinement.

As for sandals, it’s time for a caustic assessment of your toes. My podiatrist is constantly bemoaning how older men ignore giving their feet proper care. Callouses, bunions and ram’s horn toenails are far too common. So, if you want to wear sandals, get a pedicure first. Then be honest about how much of your feet you can show with pride. Avoid slide sandals that have no grip or strap in the back. They may slip off too easily and cause you to fall on an uneven surface, and then your summer footwear may wind up being an unwieldly orthopaedic walking boot.

There is only one acceptable kind of sneakers for summer: all white. The brand is of no consequence. It must be all white. That’s all.

Flip-flops are never to be worn more than 30ft from a pool or shoreline. There are no exceptions. Disregard this edict, and you will ruin whatever else you have on. And definitely never wear them on a city street. That’s just unhygienic.

Get the best sunglasses you can afford. Age is not a determining factor here. Buy a pair with polarised lenses and solid craftsmanship that fit your face without sliding down the bridge of your nose.

Don’t keep taking them on and off. You will lose them. If you do remove them, put them on top of your phone. Or you will lose them. When not wearing them, keep them in a case. Or you will ruin them. However, if leave them on indoors, no one will talk to you.

Never wear a baseball cap turned backwards. Anywhere. Ever. You look desperate, not cool. And people are laughing at you behind your visor. Especially me.