For a cool and casual look, dress in a grey sweatshirt and navy jeans — these two items go perfectly well together. Puzzled as to how to round off? Add olive canvas high top sneakers to the equation to jazz things up. There's no better way to brighten up a bleak autumn afternoon than a stylish outfit like this one. If you're not sure how to dress as a man in his 20s, this getup is a great example.