This casual combination of a navy crew-neck sweater and a denim shirt couldn't possibly come across other than seriously sharp. Rounding off with brown leather chelsea boots is an effective way to introduce some extra classiness to this look. During the winter months, when comfort is top priority, it can be easy to surrender to a less-than-stylish ensemble. However, this ensemble is a good illustration that you can actually stay warm and remain equally stylish in the winter months.