What makes a character great has SUBSTANCE. And maybe not always makes sense in the real world but will make sense in a story. A character must be dramatically sound and have a dramatic function. This means that the character needs a function and a personality. Decide what the function will be and then build on that to form a personality. Decide what traits will go with the characters function. You will be amazed as how this personality will grow. Ex: A character of a story with a funny function will have the following traits: happy, go-lucky, likes to make people laugh, sensitive, innocence or street wise, etc. A person who has a function that is mean in the story will most likely have the following traits: nasty, bad, disrespectful, etc.
Let this be your guide for your characters and let their personalities help you create a story.