Go for a pared down but casually dapper option teaming a red and black plaid flannel long sleeve shirt and a white crew-neck t-shirt. If you're clueless about how to finish off, a pair of black and white canvas low top sneakers is a safe option. As extremely hot sunny weather settles in, it's time for breezy combos like this one. When it comes to casual clothing for 20-something men, this ensemble suits almost any guy.