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In addition to Lauren's list, here are a few things I do: Give each character a distinct background. Some possible elements to vary are geography, culture, ethnicity, education, age, friends, fa...
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Source: https://writers.stackexchange.com/a/6969 License name: CC BY-SA 3.0 License URL: https://creativecommons.org/licenses/by-sa/3.0/
#2: Initial revision
In addition to Lauren's list, here are a few things I do: - Give each character a distinct background. Some possible elements to vary are geography, culture, ethnicity, education, age, friends, family. Each of these can affect a character's vocabulary, grammar, and general attitude toward the people and world around them. Even in the same family, age and birth order vary. - Give each character a definite personal history, with several significant events in their recent past. Their history will affect their general attitude. The recent past will put potentially useful joys, problems, and conflicts into their minds. - If the characters already know each other before the story begins, know the significant events of their relationship, especially their recent interactions. Write a conversation between them from a week, a month, or a year before the story starts. Have one character describe an interaction between two other characters (perhaps witnessed from far enough away that the interaction can't be heard). - Interview your characters. [Here's how I do it](http://dalewriting.dale.emery.name/2008/09/interviews/), with links to some example interviews. These interviews really helped me to understand each character's psychology and attitudes. You don't need to include any of this in the story, but the better you know your characters as individuals, with individual histories and individual relationships, the better you will be able to give them individual voices.