There’s a knack to pulling off old-timey classics. Tips for younger guys and boomers about the items worth embracing—and what’s best left in the past.

A V-neck t-shirt, for instance, works best as an undershirt and can make your neck look longer. A crewneck is your everyday kind of tee that’s great for layering or on its own. Garment-dyed tees ...

but there are also many ways to make any shirt a crop top—though stylist and content creator Caroline Vazzana is still a fan of the OG method. “I usually will opt for a classic white tee and ...