"A character has a distinctive voice - you should be able to hear them in your head and conduct a conversation with them while you're out walking. If the answers surprise you, you know it's the character speaking and not you."

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You try to get yourself into a situation where you only have to answer to yourself, where you can ask advice of people and work with your peers and mentors and things to try to do the best job that you can possibly do.

— George Lucas