I painted on a black base coat completely covering the terrain pieces. After the black base coat dried, I dry-brushed dark grey, medium grey, and light grey on the stone walls. Lastly, I did a very light dry brush of white on the edges of the top stones.
Next, I plan on adding sand and gravel. Then I will paint and highlight the ground. Lastly, I will add a little bit of homemade flock. These have been really fun to make so far, so I've already started making bases for some larger stone ruins.