A dark green blazer and black chinos are absolute must-haves if you're picking out a semi-casual wardrobe that holds to the highest sartorial standards. Finishing off with a pair of brogues is the most effective way to breathe a dash of refinement into your outfit. When it comes to dressing for in-between weather, nothing beats a knockout combo that can take you from season to season. A practical example for any guy who's figuring out how to dress as a 20-year-old guy.