For a look that's very straightforward but can be worn in a variety of different ways, wear a tank and dark green chinos. Turn up the formality of your outfit a bit by slipping into a pair of brown casual boots.
Brown Casual Boots with Tank Smart Casual Warm Weather Outfits For Men
A tank and black jeans will add serious style to your day-to-day casual rotation. You can get a bit experimental on the shoe front and lift up your ensemble by wearing brown casual boots.