If you prefer a more relaxed approach to dressing up, why not wear a black and white horizontal striped turtleneck and black jeans? Rounding off with a pair of black leather chelsea boots is a guaranteed way to bring an extra dose of class to this look. If you feel uninspired by your transitional season style options, this getup just might be the inspiration you need. As a 30-something Millennial guy, you want to start dressing maturely. If that's the case, getups like this are ideal as inspiration.