You're looking at the hard proof that a tan crew-neck t-shirt and grey plaid chinos are awesome when married together in a casual look. To give your overall ensemble a more elegant twist, complement your outfit with a pair of dark brown suede desert boots.
This combination of a tan crew-neck t-shirt and grey plaid chinos is an obvious choice for when it's time to go off-duty. And if you want to immediately perk up your look with one single piece, why not introduce a pair of white canvas oxford shoes to this outfit?