The characters always have to serve a need in the story. Everything stems from your main character. That’s your point of view. That’s the drive of the story. The main thing I do is just ask myself a lot of questions. How does this character see himself? How do other characters see this person? Unique characters come from flaws and quirks and you know kind of shades of grey? Once you have a character that has some of those that feels real to your central character, finding those other characters that will push that character out of his or her comfort zone, speak a truth to them that they won’t listen to, and bring out the flaws in your character, they all kind of build from there. And then you can ask yourself those same questions about those characters as well and build them out.