I think I've lost some of the life I put into my gestures. I'm not great with anatomy anymore, either. I still have a good taste for form, though. I did this: [link] without any shade references. The best part, though, is that bottom lip. XD I just always kinda knew where shading went.
It's basically quick sketching of a model. You take, say, thirty seconds to draw a really quick and simple sketch of the model and their pose. It's not so much about capturing detail as it is about capturing the essence of a figure and its movement. It can help with proportion as well as other things.