Such must-haves as an olive turtleneck and dark green chinos are the ideal way to inject effortless cool into your casual styling repertoire. A pair of athletic shoes introduces a relaxed aesthetic to the outfit. Can you see how very easy it is to look on-trend and stay warm when chillier weather comes, all thanks to combinations like this one? Those wondering how to sport edgy casual style as you go through your 20s, this ensemble should answer your question.