My character sheets contain the following information:
• physical statistics
• motivation and plot relevance
• character connections and how they perceive other characters
• history as it relates to the plot and world
• general outlook and personality traits
I don't need to know who their first crush was or what color their underwear is--unless it's relevant. Everything else can be made up along the way so long as it works.
The most important things on that list, imo, are motivation and plot relevance, which usually ties directly into character connections. Take THE HUNGER GAMES, for example.
What was Peeta's motivation? To protect Katniss and ensure her survival. His plot relevance, specifically, was to first garner sympathy from the viewers (star crossed lovers), then to protect Katniss from the Career tributes, and finally to provide something of an emotional arc later on when Katniss risked her life to return to the Cornucopia and retrieve the medicine for him. All these things are results of their character connections--their history together. Peeta is the boy with the bread. He saved Katniss from starving when they were kids, and his admiration for her eventually grew into love. Thus tying back to his motivation--ensuring Katniss survives The Hunger Games.
This information builds the foundation for your character. These impressions are what the reader will carry with them through the book. Things like his favorite color (orange, I think, was Peeta's) are nice details but not necessary at this stage and can always be thought up later on as needed.
But what about voice?
A character's voice usually becomes more clear as I start writing so, for a character sheet, I tend to gloss over those. But if I'm looking for a stronger grip on a character's personality, I'll do a character interview. An interview helps settle voice and pick out some personality quirks. Then, for fun, I'll sometimes do a bust sketch to help me visualize him/her.
What can you intuit about this character?
Have a great week, all! ♥