This laid-back combination of a white crew-neck t-shirt and black jeans is very easy to throw together in no time flat, helping you look amazing and prepared for anything without spending a ton of time searching through your closet. Infuse a dash of stylish effortlessness into your outfit by finishing off with a pair of athletic shoes. During the winter months, when warmth is crucial, it can be easy to surrender to a less-than-stylish outfit in the name of convenience. But this outfit is a stark illustration that you totally can stay toasty and remain equally stylish during the winter months. When it comes to casual dressing ideas for 20-year-old gents, this outfit looks nice on almost any guy.