This pairing of a brown crew-neck sweater and a light blue long sleeve shirt is very versatile and really apt for whatever's on your to-do list today. If you need to effortlessly dial down this ensemble with footwear, add a pair of grey athletic shoes to the mix. So as you can see, this look is a really savvy choice, especially for transitional weather, when the temperature is starting to drop. Relaxed casual ensembles for teen guys aren't actually that hard, as you see here.