I recently finished a first draft of my manuscript. As I tried to draw it to a close, I started seeing things I had failed to develop along the way.
At the end of the book I asked my husband to describe my characters to me. What he said wasn't nearly as helpful as what he didn't say. For the most part I had not reminded my audience what my characters looked like since they first met them at the beginning of the book. As consequence my husband had to think hard to remember and even then could only remember small things like “so and so was really tall and the other guy was really short.”
I have a short list of physical attributes that I bring up for each of my characters, the rest I leave to the readers imagination, but even my short list was forgotten for lack of reminders. For instance, one of my characters has burgundy eyes. I mention this around chapter three, but never again. There is no way my readers are going to remember this after nineteen more chapters without even the slightest reference to it. What was I thinking?
For each of my characters I need to go back through my story and find appropriate places to gently remind the reader of my characters' unique traits.