DeviantArt also has many grunge brushes for download.

Another thing is the ground itself. It still looks too "nice". I would think that the efforts of setting up the camp and fencing and dragging around stuff would have gouged and damaged the grass more than the slight wear shown.

A question might be - how long has the camp been there? How did the materials get brought in? Were any horses/wagons used? If so I'd expect to see ruts and clods all over the place.

Lastly, is the fire a cook-fire or a warmth fire? I would expect more around the camp, possibly with logs and things pulled up to sit on.

-Rob A>