Characters are the heart of fiction. If they aren't breathing, people can't connect to your writing. So how do you get them to breathe? That's the problem and the struggle. There are plenty of books that will talk about creating elaborate character sketches or filling out this form or that questionaire about your characters. These may, in fact, help some people come to know their characters better and so help them breathe life into them. But by themselves they aren't enough to create living, breathing characters. Why not? Because they are working from the outside. They're trying to force the character to move and act from a set of characteristics the author has created. But unless the author can use these methods to actually create a character who is living in the story the character will make the wrong choices and she won't come to life.
What the writer has to do is find a way to be inside his character and move the character forward with the story. To do that the writer needs to create a kind of circulation connecting the character with the other elements of writing fiction: setting, plot and subplot, narrative drive, language, other characters etc...all of these need to work together, each scene adding to what was before it and connecting to what will come after. It's helpful when writing to keep thinking about making connections. Characters do things for reasons. Sometimes the writer doesn't see these clearly. Fortunately, unlike life, writers get to revise their work. In the revisions the connections will become clearer and clearer and by working to discover these reasons and linking them to the other characters and the story, the characters will begin to breathe.
Or so I think today.