OOh ooh here's a technique that I've found really effective with stuff like fur. I take all the line art of all the fluffy fur, I make it a selection, then I make it its own layer. Then I make it a smart object. And from there I use a series of radial blurs to fluffy them up.
I'm NOT saying my images are any better. I think this one turned out looking nice. I just thought I might share a technique that seems like it works well for me.