A tan long sleeve shirt and beige jeans are great menswear essentials that will integrate brilliantly within your day-to-day off-duty routine. Class up this look with a pair of dark brown leather casual boots. When leaves turn yellow and red and autumn starts to take over, you'll appreciate how ideal this look is for unpredictable fall weather. Guys who are curious how to pull off smart casual outfits as you move through your teen years, this combination should answer your question.