Paint (darker and lighter gray OR earth tones and red)
Using the textured paint and the trowel, create large stone bricks on your wall. Let everything dry completely.
Paint the entire wall with the darker color (whether grey or brown) and let everything dry once again.
Using a sea sponge, dab on the lighter grey or brown, then add a little red here and there.
Jennifer Ofenstein (ofenjen)'s tutorial was taken with permission from sewhooked.com.