Get a jump start on the season with the five trends taking menswear by storm: the easygoing patterned double-breasted blazer, performance sneakers worn with a suit, a new breed of elevated sportswear, well-cut trucker jackets in non-denim materials, and a fresh wave of elegant blue suiting. Plus: Z Zegna's Paul Surridge offers his tips for transitioning into spring, four upstart fashion lines to know, and everything we love right now in the world of style.