Next up on the list of reader gripes is when the characters are all the same. This occurs primarily with inexperienced writers who don’t know how to develop a character properly and just plug a name into the action without bringing him, her, or even it, to life.
Characters should be as distinctive as possible. They shouldn’t look alive, talk alive, or behave alike. The more contrast, the better. Best case, the reader should be able to tell them apart from their dialog alone. Give them speech patterns and mannerisms that make them into a unique person. Interesting characters are what draw readers into the story as much as the plot line. If you don’t care about the people in the story, it has little impact. Building memorable characters is a skill every author should develop.