A black long sleeve t-shirt and navy jeans are absolute menswear essentials if you're figuring out a casual wardrobe that matches up to the highest sartorial standards. Feel uninspired with this ensemble? Enter a pair of black leather casual boots to mix things up a bit. As you can see, it's extremely easy to look awesome and stay snug come fall, all thanks to combos like this. Overall, an ideal demonstration of casual fashion for teenage boys.