Why not consider wearing a black shirt jacket and black vertical striped chinos? As well as totally practical, these items look amazing paired together. The whole ensemble comes together when you introduce desert boots to the equation. After all, when do you wear casual looks like this if not at 20?
Try teaming a black shirt jacket with charcoal chinos for a simple look that's also well put together. Finish off with desert boots and you're all done and looking incredible. Sartorial inspiration like this will help you remain incredibly fashionable as you make your way through your 20s.