There are many different ways to add these sorts of effects. The simplest way I've found is to use gaussian blurs. Rotoscoping itself is basically and exercise in patience. I might be able to help you. I've had some good results...inconsistent, but good.
Please keep in mind this was a rush job. was just looking for a 'roto' example i'd done.
I'm still catching up with the various ep3 edits and whatnot.