Lucky you; your slim profile lets you pull off the most challenging fabrics and cuts, but beware! When anything is possible, even bad ideas can seem like good ones!
Your number one choice to look current, professional, and attractive, is a European-cut suit. With trousers and jacket fitted tightly to the body, this is a silhouette that only you can wear well. Heavier men tend to look like they’re ready to burst from a sausage casing in a slim-cut suit.
You even have the option of a three-piece suit, the vest giving a layer on the upper torso that helps create that masculine V-shape. A sweater vest will have the same effect, with a softer look; this can be a great choice if you tend to have an assertive personality.
When it comes to fabrics, you can carry off anything. Heavier tweeds and the like will add a bit of bulk, and tend to look best in drapier, looser cuts. A high S-number wool in a sophisticated finish will look outstanding in a Euro-cut slim fitted suit. You’ve seen Tom Hiddleston and Benedict Cumberbatch wearing these looks on television a million times. Contrast the way Cumberbatch’s signature tweed coat gives him an almost military, assertive presence with the way his sleek suits give him a cool, sophisticated attitude.
For lapels, you truly can wear anything from a shawl to a peak to a notch; avoid Nehru or Mandarin collars, both because they can make your head look big and because this isn’t 1969.
Pockets, particularly flapped pockets on a dead horizontal, can work against the strong vertical, so if you fear you’re too beanpole-y, a jacket with flapped pockets can help balance you out. If you like looking long and lean, slanted pockets with no flaps are best.
Since you haven’t much junk in your trunk you can chose no vent, a single vent, or a double, and always remember that the double vent will move more and reveal more of your suit’s lining, so why not go for a snazzy contrasting colour? A bit of sartorial surprise can be a good thing.
If your face is a long oval, you might find a British Spread Collar on your shirt will work well to counteract the sheer verticality of your presentation, and it shows off a good tie like no other collar. And French cuffs can look terrific on a long, lean arm.
Altogether, you can get away with the details that they shorter, stockier man should avoid, and you’re entitled to have fun with it.