Background

A character is the representation of a person. My guess is you knew that.
The reader should be able to identify with and care about the characters in the sense that the characters seem real to the reader.
The characters must do something, and what they do must seem reasonable for them to have done it.

Introduction of Characters

Characters should be introduced early in the story.
The more often a character is mentioned or appears, the more significance the reader will attach to the character.
The main character should be introduced before setting so that the setting can be introduced from the point of view of the character.

The nature of characters can be brought out through minimal description and the actions, thoughts, and dialogue of the characters.
The writer should allow the reader to make judgments about the characters; the writer should avoid making the judgments for the reader.
The feelings of the character should be demonstrated rather than told by the narrator.

The nature of characters can be brought out through minimal description and the actions, thoughts, and dialogue of the characters
The one rule about writing is that there are no rules. If it works, it works.

Cardboard characters.
- A cardboard character is one who’s a stereotype.
- They are a character whose every action or reaction is exactly what the reader would have guessed for the situation.
How to Avoid Cardboard Characters
- Avoid them by inventing lives, backgrounds, attitudes, quirks, moods, etc. for all characters.
- The bigger the character is, the more depth he or she gets.
- Even the barista whose only scene is taking other characters’ order and bringing the coffee has a unique personality which needs to come out, however briefly.