Locations in your book should be as well defined as characters because, in fact, they are characters. Locations are living and breathing. Like people with hearts and minds and souls, locations also have hearts (the community of people that reside there), minds (the government and systems of the community) and souls (that indefinable spirit of a place). So do yourself a favor and treat your setting as though it were a main character. Give it spirit, give it history and eventually you’ll find that the location has its own set of needs and desires.