Pair a black crew-neck t-shirt with black skinny jeans for a city casual outfit that's easy to wear. Take your look a whole other path by wearing a pair of white and black leather low top sneakers. So as you can see, it's very easy to look on-trend and stay snug when chillier weather comes, all thanks to outfits like this one. As you can see, as a 20-year-old gent, you have a vast array of styling options.