Make a navy vertical striped blazer and a black long sleeve t-shirt your outfit choice to create a neat and relaxed outfit. Amp up the cool of your ensemble by finishing with a pair of grey canvas low top sneakers. This combination isn't a hard one to nail and it's season-appropriate, which is important when it's extremely hot outside. And if we're talking casual dressing ideas for 20-something gents, this ensemble looks nice on most men.