This relaxed casual pairing of a crew-neck t-shirt and olive overalls is very easy to pull together in seconds time, helping you look seriously stylish and ready for anything without spending too much time searching through your closet. Don't know how to round off this look? Round off with black and white canvas low top sneakers to amp up the fashion factor. When it comes to casual style for 20-year-old gents, this getup suits almost any gent.