When the setting allows casual style, you can easily go for a bomber jacket and a crew-neck sweater. Inject a hint of class into this outfit by finishing with a pair of brown suede brogue boots. When staying inside on a crisp winter day is not possible, this look just might get you through the day. As a 30-something Millennial gentleman, you want to start dressing more professionally. If that's the case, combos like this are ideal as inspiration.