One of the best ways for a man to style out such a functional item as a brown shirt jacket is to pair it with a white polo neck sweater. Balance out your look with a dressier kind of shoes, like this pair of dark brown suede tassel loafers. As the weather is getting warmer, it's time to get rid of those bulky winter gear and choose something lighter, like this look here. As a guy in his thirties, you probably want to start dressing more maturely. In this case, outfits like this are a never-failing option.