When the setting permits off-duty dressing, you can always rely on a white long sleeve shirt and dark brown chinos. Balance out this outfit with a more refined kind of footwear, such as these brown leather tassel loafers. This combination shows that dressing well in your twenties is quite manageable.
For something more on the casual end, try teaming a white long sleeve shirt with dark brown chinos. For something more on the elegant end to finish off this getup, introduce a pair of brown leather tassel loafers to the mix. Sartorial inspiration like this will help you remain incredibly fashionable as you go through your 20s.