Also you might want to make some of your headstones tilt a bit. It looks like an old cemetary but it is too perfect. I load my props and then get a picture of what I want in my head and try to move stuff around to match that picture. Lighting is important for shadows and depth. Don't get discouraged it takes time to get it just right. Go out and find some cemetary pics you like and see if you can get that look then work on your own. 
Marque