1. Your two-button starter-suit phase is over. Go all in on mile-wide peak lapels and a C-suite double-breasted cut. 2. There’s no greater suiting sin than a wimpy collar. Stock up on dress shirts with a strong, substantial point, like this crisp, striped rendition from the fresh-faced London tailor Speciale. 3. For most of the 2010s, slim—and often downright skinny—suiting reigned supreme. Then, as the decade turned, silhouettes loosened to roomier, slouchier, more expressive proportions. These days, we’re after a happy medium: suits that just fit, period, neither under- nor oversized. 4. Trad details like pleats and cuffs used to be telltale signs your pants were hopelessly fuddy-duddy. Now, along with a fuller, more flattering cut through the leg, they’re once again proof you have a great tailor and know how to talk to him. Anglo-Italian Glen Plaid Sky Overcheck Double-Breasted Suit Speciale Cotton Stripe Shirt Midtown Uniform, Hold the Mid Tech bros and finance guys tend to catch flak for their sartorial choices. But the basic elements of their day-to-day looks—logo-happy baseball caps, comfortable …