I've noticed that many artists have these peculiar ways of handling the initial drawing process. Karl Kopinski visualizes his characters on the paper and makes fluid scribbly lines for his underdrawing before inking. Claire Wending was shit at life drawing but somehow became great at figures. She 'feels out' the shapes and then draws these complex poses from imagination. I've also seen a bunch of Japs make random looking scribbles that become solid figures. These methods seem to be great for producing more lively work.

How do you reach that level of skill? Is it something that comes with time or do I have to activately change the way I draw?