Add a little flat brown or perhaps even beige to the red to get a more "toned-down" look. then come back and pick out a few bricks in a variety of shades, such as dark brown, brown, even a few pinkish tans... take a look at one of the buildings I sell on my site for a better idea of what I mean here.... (picture is worth a thousand words, right?). If nothing else, try adding a light grey wash to the final piece to give it a dusty "mortar" look.
