Identify the function of the character in relation to the protagonist. He may be the protagonist himself, or an antagonist, supporting character or foil.
Consider your character's contribution to the story to determine whether he is a major or minor character. Major characters are not only those who appear the most often, but also those whose actions contribute significantly to the story.
Compare the character's circumstances and personality at the beginning story to those at the end to determine whether he is a round or flat character. Round characters change throughout the story, while flat characters remain the same.
Examine the character's actions, interpreting them in the context of the time period and location. Like real people, what a character believes is displayed through what he does more than what he says. Especially note the character's moral choices.
Explore the results of what the character does. Often, if a character's actions ultimately yield positive results, the author intends to portray these actions as right or noble. If they yield negative consequences, they are wrong or ignoble. Consider the way in which a character's actions affect others as well as himself.
Investigate the choices that other characters made in similar situations. These often demonstrate other available courses of action that the character might have chosen. The things that he did not choose to do say much about his personality and values.
Evaluate the character's motivation. Why he acts as he does is often as important as the act itself.
Read the character's dialogue carefully. While words do not carry as much weight as actions, they often clarify or contradict the character's actions, thus painting him in more detailed strokes. Also note what the character fails to say.
Note what other characters say about him and interpret these comments in the light of who those characters are in relationship to the character you are studying. For example, if the antagonist says something negative about the character, it might indicate a positive trait. However, if a sympathetic character says something negative, it may indicate a personality flaw.
Note the character's physical appearance, including his features, clothing and accessories. Sometimes these mirror the character's traits; other times the author uses them as a foil, or a method of contrast, to highlight what the character is not.
Examine the text for any recurring items associated with the character. These can also serve as a commentary on the character.