Speech
The following is an example of a method one uses to reveal a character: Alice uses fancy words to reveal her nature, and Dam reveals his nature by using slang,
private thoughts
The following is an example of a method one uses to reveal a character: We learn how a character may feel as he sees a bully picking on a smaller kid.
Appearance
The following is an example of a method one uses to reveal a character: The man was described as a tall slender man with a distinguished look.
How other characters feel about them
The following is an example of a method one uses to reveal a character: A salesman might be a good guy to his customers, but a cranky guy in the eyes of his family.
Actions
The following is an example of a method one uses to reveal a character: Scrooge worked on his accounts on Christmas Eve.