Why not dress in an olive crew-neck t-shirt and cargo pants? These two items are super practical and will look cool teamed together. Bump up the dressiness of this outfit a bit by rocking white canvas derby shoes. So as you can see, it's a sharp, not to mention season-appropriate, getup to keep in your seasonal closet. Casual outfits for stylish guys in their 20s aren't actually that hard, as you see.