Consider wearing a grey short sleeve shirt and a charcoal crew-neck t-shirt for a sharp, casual outfit. Round off with a pair of black leather casual boots to add a confident kick to the getup. As you can see here, it's extremely easy to look seriously stylish and stay cozy when colder days are here, all thanks to combinations like this. Casual getups for stylish 30-year-old gentlemen aren't actually that hard, as you can see.