Originally posted by: Guy Caballero
And yet, American Graffiti is loaded with great performances, by young, unproven actors! Wha' happened?

He had good actors in a story that was realistic and natural and that the actors could relate to and play with. Lucas did absolutely no direction actor-wise on the film, instead relying on a well-written script that was spruced up by Gloria Katz and Willard Huyck and that was very real because it was based off his adolescence, and instead filmed the movie documentary-style by pointing the camera at the actors from a distance and letting them improvise. A dialog coach was hired for any actor directing while Lucas supervised Haskel Wexler and the camera-related matters. Basically, American Graffitti was made in such a way that the performances came out natural. Lucas wasn't an idiot either--he knew he couldn't direct actors so he just let the actors go through the scenes on their own, and this plan was successful because the movie took place in a fairly modern time and with scenes and dialog that any 17 year old actor could relate to and realistically deliver. Lucas was even famous for using only the takes in which the actors made mistakes--lending their performances that awkward, unscripted natural quality that the film is famous for.

If you look at American Graffiti and Attack of the Clones you would never know that they were written and directed by the same man--the difference is that Lucas' lack of direction was perfectly suited for the contemporary comedy-drama but not at all for a melodramatic space tragedy.