A navy long sleeve shirt and black chinos will convey this relaxed and dapper vibe. A trendy pair of derby shoes is a simple way to inject an element of sophistication into this getup. This look is most probably what you've been looking for as a teenage boy.
Navy Long Sleeve Shirt with Derby Shoes Smart Casual Warm Weather Outfits In Their Teens
A navy long sleeve shirt and beige chinos are a nice outfit to keep in your current casual lineup. For extra fashion points, introduce a pair of derby shoes to this ensemble. As you're progressing through your adolescence, you probably want to look older. In this case, looks like this are a life saver.