This classic and casual pairing of an open cardigan and charcoal dress pants is super easy to put together in seconds time, helping you look stylish and ready for anything without spending a ton of time going through your wardrobe. Finishing off with a pair of slip-on sneakers is a surefire way to bring a dash of stylish nonchalance to your ensemble. Casual ensembles for stylish 20-something gents aren't actually that hard, as you can see.