I do something sorta strange with my art students that helps them with a difficult pose. When they can't nail down a figure's pose the way they want it, I have them get in that position and "feel" the pose. Often times, they discover that why the drawing looks odd is because there's no comfortable, physical way the figure can move like that.
I tend to write the same way. When I come up with a difficult scene, I actually get up and go through the movements each character might make. Where are their hands? What are their facial expressions? I mumble lines while I'm walking. Of course, it's rather humorous to be caught doing that. My friends think I'm in pain when they pass me and my face is all scrunched up in a wierd way. Too funny.
I reserve the physical acting part when I'm alone at my computer. Otherwise, my family might have me committed. This trick does work to help solidify a scene, though. I'm a true believer in visuals.