Round Characters

• Generally, effective writers aim for round characters, characters that are full of detail, react believably and make believable decisions. The complexity and intricacy of round characters make them interesting and instill empathy in the reader. Scout from Harper Lee's "To Kill a Mockingbird," for example, is a round character: she is endearing and funny, yet her naivety influences her beliefs about the world and leads her to make mistakes.
  
  

Flat Characters

• Flat characters, on the other hand, do not possess many layers of complexity. Flat characters speak, act and look typical. They usually do not surprise the reader, but paradoxically, in that way they are not realistic. Amateur writers often produce flat characters. However, a flat character in the hands of a skilled writer can have an interesting effect. Many characters in "The Lord of the Rings," such as Gandalf or Sauron, for example, behave as one might expect, yet their characters fit the genre and the purpose of the story.
  
  

Static Vs. Dynamic Characters

• Static and dynamic characters are related to flat and round ones. Static characters do not change over the course of a story. They do not learn or assimilate new perspectives and do not develop their traits or thinking. In an effective story, characters go on a journey and arrive somewhere. That is, a good story leaves the reader with the impression that the main character has arrived somewhere or learned something. The character the reader ends the story with is not the same one he started with.
  
  

Major and Minor Characters

• The main character in a story is the protagonist. Her nemesis, or the person that works against her, is called the antagonist. An antagonist creates problems for the protagonist that she must overcome. This is partly what drives plot. Characters, whether major or minor, can also serve as foils to the protagonist, or any other character. A foil offers a contrast to another character that helps amplify his traits, thoughts or actions. Famous foils in literature include Dr. Jekyll and his evil counterpart, Mr. Hyde, and Watson and Sherlock Holmes, the assistant vs. the genius detective.