Go for a pared down but at the same time cool and casual outfit marrying a navy crew-neck sweater and teal chinos. If in doubt about what to wear when it comes to footwear, stick to a pair of black canvas slip-on sneakers. This look is a really savvy idea, especially for fall, when the mercury is dropping. Those who are curious how to wear cool off-duty outfits as you progress through your teens, this combination should answer your question.