A character is never good enough until you think they are (good enough).
Do they seem like a real person?
Can others relate to them?
Do impartial readers (not just your friends, although havin your friends read your work is great!) think this character is believeable?
These are all signs of a good character.
For more info, see post ’Seminar 1 Part 2′, especially the part about Mary Sues and Gary Stus.
