How your Soft Blazer should fit
The Shoulders
Make sure the seam hits right at the end of your shoulder. Just because the shoulder is soft and unstructured doesn’t mean you can fudge the fit. Actually, fit is even more important here, where extra fabric in the shoulder will bag out due to lack of padding. As with all jackets, the fit of the shoulder is crucial, because it’s difficult and complicated to alter. Too baggy or too tight, leave it on the rack.
The Lapels
Your flat hand should slide comfortably between the lapel area and your shirt when your jacket is buttoned. If you ball up your fist, the jacket should pull. And remember a medium width notch lapel works best with a soft blazer because it doesn’t overwhelm the unstructured shape with the pomp and bombast of, say, a peak lapel.
The Buttons
The top button of a two-button blazer should hit more than a bit above the navel (and never, ever, ever below the navel). Your soft blazer should be a two-button affair because it’s medium gorge and classic lines help anchor the jacket and pull its tailored silhouette together.
The Sleeves
The sleeves should hit between your first thumb joint and your wrist. And, as with all jackets, make sure to get them tailored so a quarter to a half-inch of shirt cuff falls below your jacket. Otherwise you’ll have overly long gorilla arms.
The Lining
A soft blazer with no lining is, well, softer than a lined one, and this will let it hug your body, giving it the easy-wearing versatility of a nice cardigan.