I used a trick from Ian Rice for these bricks:

After spray painting the wall white, I used Prang art pencils to color the brick. I overlayed reds, oranges and browns until I was happy with the coloration. I also used a gray pencil to color the window sills.
Nick
If you hadn’t told me what you did, I would have guessed that you bought them. They look really good.
Keep up the good work.
Looks great. I’d like to give that method a try. I’m curious as to the technique used. Did you color each brick individually or rub the pencil over the entire wall in a dry brushing sort of way?
Tom
I used the side of the pencil, and rubbed it over the entire wall. You can color each brick individually with the point, but that takes a LONG time. I did, however highlight a couple individual bricks this way.
Also, because the pencil is light, it will take several passes to build up a good color.
Nick
Looks Good. I wonder if the same thing could be done with pastels? Might be worth trying.