I've painted some GW craters as shellholes and I've put some remains of barbed wire on them to add some detail, and also to see how it looks. It took me too much and it could look better:
-First I tied some Army Painter wire to the poles.
-Then I tied some "knots" to the wire and cut them to make it look like the real thing.
-I painted the whole thing black, then I painted the wire in dark grey.
-After drybrushing the wire in reddish brown (is "reddish" a word?), I painted the poles trying not to stain the wire.
Is there a better way? How would you have done it? By the way, the Games Workshop craters are nice, but they're that, meteorite craters and not shellholes.