For an off-duty ensemble with a modern finish, make a beige cotton blazer and dark green cargo pants your outfit choice. Complement this look with black leather derby shoes for an added dose of style. This combo is also great if you're hunting for summertime wear to get through a tedious day. As you're maturing from your 20s to your 30s, you want to start dressing more like a mature gentleman. In this case, combinations like this come in very handy.