Several times, I've had it suggested that I should try coloring the tiles. I've been a little skeptical, but I tried an experiment. I took a sheep tile and got some green wood stain from Cole's Hardware and went to work. I doubled the coat on half the tile, you should be able to see the difference in the pic.
Personally, I don't like it. A lot of the beauty comes from the wood, and the stain seems to just cover it up. I'm planning on making tile sets available so if you disagree, please buy one and stain it. Maybe my technique is wrong and I just need someone to show me how it's done.