Tomorrow (or everyday if you would like) pick a character from any of your stories. As you go through your day, keep them in mind. Every time you have a situation or problem to react to or solve, try and imagine what your character would do. Not only will this help understand and build your character more, but it will also help to write out your story in your own writing voice. This challenge is also helpful in editing and revising when a scene doesn't feel write or a character is out of character. Try this exercise if you have writer's block or if you can't figure out how your character would react.