If you're looking for a casual but also sharp ensemble, wear a sweatshirt with a denim shirt. For something more on the elegant side to finish off this outfit, complement your ensemble with black leather casual boots. As you can see, it's very easy to look dapper and stay warm when cooler days are here, thanks to this outfit. Those who wonder how to pull off cool casual looks as you move through your 20s, this combination should answer your question.