Pair a beige polo neck sweater with a white crew-neck t-shirt to assemble an interesting and modern-looking ensemble. A trendy pair of black canvas low top sneakers is an effective way to add a dose of stylish nonchalance to this look. This getup is a nice option if you're piecing together a well-coordinated look for summer-to-fall weather. Smart casual ensembles for stylish teenagers aren't actually that hard, as you can see here.