After the exterior was given a coat of gesso and then a coat of tan paint, (Fawn from Americana acrylic paint), I started on covering the window edges with brick trim made out of heavyweight card stock.
I used cereal boxes to make my red brick strips, then painted them a rusty color and glazed over them with a burnt umber wash. You could also use styrofoam, two thicknesses of card stock or bristol board - whichever you like.
I cut out the little bricks and glued them to card stock. Then I used a matte varnish on them and when that was dry, I used vinyl spackling over the bricks for mortar and then wiped it off. I glued them to the windows and added a keystone in the middle.
I coated the tan block brick strips for the window sides and trim with gesso and let them dry completely after scoring the lines and pulling a layer of paper off between the blocks. Then I painted them with FolkArt acrylic color called Linen. Then I glued them to the window frame sides before giving them a light coat of spackling and wiping it off to simulate mortar. The window frames fold in to cover the edges completely and really add to the brick look. Love the way all the edges are covered. It really gives a finished look to the house.
Even the little basement windows have trimmed edges. A light coat of spackling wiped on and then off gives the trim a cement look. I love that technique.