Consider wearing a black denim jacket and a navy crew-neck t-shirt if you want to look cool and relaxed without exerting much effort. Clueless about how to round off your outfit? Rock brown leather casual boots to ramp up the style factor. This one is a nice pick if you're picking out a knockout getup that will take you from summer to fall. If you're not sure how to dress as a gentleman in his twenties, this pairing is a good illustration.