[George Lucas] has a binder, like this green, literally like an old style trapper keeper. And in it, it has like his name written in the front of it, just like you would write in school. But this is the original binder that he notated “The Star Wars.” And in it are of his handwritten notes that go back to like 1976, ‘75, and you see these names written down, and you see like Tatooine written down and Macey Windus in there, like all these different character names and stuff.

And he’ll open it up and be like ‘well, we need a character name’ and he’ll go through and he has a whole bunch of pages of planets and names. So he’s still sourcing from a lot of original material for what we do in “Clone Wars” the same way he did in the prequels and the original trilogy.

He pulls out old style Ralph McQuarrie, Joe Johnston, John Mollo designs and we put them in the show, and again, he’s such a key cohesive part of what makes this feel more like Star Wars. Cause we never set out to make our version of it. We’re like, ‘George, we just wanna continue what you were doing and try to make it great.’

Dave Filoni, talking about working on The Clone Wars with George Lucas at Celebration VI {source}