For an off-duty ensemble, pair a black long sleeve t-shirt with beige chinos — these pieces play perfectly well together. If you want to effortlessly level up this ensemble with a pair of shoes, add black chunky leather derby shoes to this ensemble. Pay attention to looks like this if you want to add seriousness to your 20-year-old's wardrobe.
This combination of a black long sleeve t-shirt and brown chinos is hard proof that a safe casual getup can still be really interesting. For shoes, you could go down a more classic route with black chunky leather derby shoes. Overall, a perfect demonstration of 20-something style.
If you're looking for a laid-back but also dapper ensemble, wear a black long sleeve t-shirt with navy jeans. If you wish to easily step up your outfit with a pair of shoes, slip into a pair of black chunky leather derby shoes. This getup is most probably what you've been looking for as a gent in his 20s.
If you like the comfort look, try teaming a black long sleeve t-shirt with olive shorts. Want to dial it up in the footwear department? Add black chunky leather derby shoes to this ensemble. Laid-back looks for stylish 20-year-old guys aren't actually that hard, as you see here.