You have to play around with the settings on your camera........try some with the 'macro' on and some with it off.........with flash and without........it's a tricky thing (and a decent camera doesn't hurt either), but it's all about time and patience......as I've stated before, you just 'know' when the shot is there!!
But Craig did have a really good point as well..........switch the angles of the figs against the light source........does wonders for the play of shadows!!!
