Rag & Bone, $255
With the recent spate of heat waves sweeping North America, the subtle art of layering is likely the last thing on your mind. However, as Ryan Reynolds recently taught us, donning a lightweight cardigan is an easy and effective way to add a little polish to a casual outfit. Knit from a soft jersey (like your favorite T-shirt) or a breathable blend of cotton and wool, a cardigan can take you from the office to the bar with ease, whether pulled over a basic tee or paired with your standard button-down and a tie. And should things get too steamy, feel free to peel it off, ball it up and throw it in your bag, desk drawer or car.