Perfect the semi-casual outfit in a black suit and a black turtleneck. When it comes to footwear, this getup is rounded off well with black leather derby shoes. This ensemble is probably what you're looking for as a 30-year-old guy.
Black Leather Derby Shoes with Black Suit Smart Casual Warm Weather Outfits In Their 30s
This look suggests it pays to invest in such menswear items as a black suit and a white crew-neck t-shirt. Finishing off with a pair of black leather derby shoes is a guaranteed way to bring some extra depth to this getup. This ensemble shows that in your thirties your outfit options are looking great.