You know how they say that every villain is the hero of his or her own story? Well, every single character in your stories is the main character of their own story. And as an author, you have to have a pretty good idea of what their story is like. You need to know every single character in your story. You have to know who they are and why they are who they are. So...how do you do it?
Knowing Your Characters
Authors have an intimate knowledge of their main characters. Their thoughts, their backstory, their hopes and dreams. But as an author, you should have this information for all of your characters. Every character in your story, no matter how minor, matters in their own story. You need to know what drives them and what makes them who they are. Otherwise, the actions your characters take and the words they say may not make any sense.
It helps to create a character sheet to remember essential facts about each character in your story, like what their names are and what they look like. While you're jotting down quick notes about hair and eye color, include essential elements of their personality as well. Keep your notes as short and to the point as possible. You don't want to read for 40 minutes every time you want to write a chapter.
If you don't know every character inside and out, you can't write every character in a believable way. Know why each character does what they do and says what they say and you'll be creating a well-crafted, well-written story. Because if you don't know your characters, none of your readers can know them, either.