Are your characters invisible? Are they all alike with no defining characteristics, or are they clearly illustrated, through your use of words, so that you know one from the other without taglines?
How do you define your characters? Is it by physical description? Is it by their pattern of speech? Is it by their actions and interaction with others? A well rounded character is defined by all of these things.
Study the characters in your favorite stories and books. Which ones do you like? Which ones do you dislike? Do you feel strongly about them or just so so? What characteristics do your favorite characters have in common? In what ways are the characters different? Are the characters ordinary or extraordinary? If the MC had been different what effect would it have on the story?
Type the text of your favorite story, or a chapter from a favorite book. Using colored highlighters, highlight all of the text that defines your favorite character in one color for each category of physical description, speech, and actions. Review each of them separately. Which of these things is most important to your impression of this character? What do I learn about the protagonist from the other characters in the piece? Is this character perfect, or flawed, a balance of good traits and not-so-good traits?
Do this with the antagonist as well. What is it about this character that you don't like? What did the author do to make you dislike this character? Does the antagonist have any redeeming qualities?
Try this study with other story or book characters. Pay close attention to how description is slipped into the story seamlessly so that it adds to the story without stopping the action. Is that description important or necessary to the storyline? Would it be better to leave it out?
After you have done this a few times it is time for the real test. Print out a copy of one of your manuscripts. Highlight the MC just as you did with the other stories. Take a deep breath and read over the highlighted information. Are all of the elements there that were in the other stories? If not, what is missing? Do the same with your antagonist.
Use that information to fill in your characters and make them visible, so that an editor will love them as much as you do.
(c)2006 Sharon A. Soffe