So as you can see, it doesn't take that much effort for a man to look casually smart. Just rock a dark green overcoat with a white knit turtleneck and be sure you'll look amazing. Go off the beaten path and switch up your outfit by rounding off with a pair of black leather brogues. In your 30s, you want to start dressing maturely. If that's the case, inspiration like this proves very useful.