Character descriptions can be tricky. It's easy to fall back on the obvious; tall, dark hair, green eyes. If you want to flesh out your characters and make them really come alive, describe something about this person that is unique to him or her.
Author Jody Hedlund has an excellent article on describing the characters in your writing. http://bit.ly/pQVtHq
I have the honor of previewing Jody's new book The Doctor's Lady which will be out on September 1, 2011, and interviewing her on this site. Watch for it soon.
