The best choice for a cool and casually sleek outfit? A trenchcoat with a long sleeve shirt. On the shoe front, go for something on the dressier end of the spectrum by slipping into a pair of black leather double monks. This is a goofproof option for a stylish winter-to-spring transition ensemble. As you're going from your 20s to your 30s, you probably want to start dressing more like a grown gentleman. That's when looks like this are a foolproof option.