Books that are on my writer’s shelf:
Edelstein, Linda N. PH.D., “Writer’s Guide to Character Traits, Second Edition”– This is a fantastic text for rounding out your characters. It presents correlated personality traits for individual personality types, psychological diseases (youth and adult), occupations, etc. It also includes a handy cross reference so you can take something like “driven” and find that is a trait of “the perfectionist” who also exhibits vulnerability to criticism, inability to turn to others for help, and susceptibility to self doubt. I found it helpful in identifying a personality type for my characters and then using actions to “show” the range of related traits for that character.
Card, Orson Scott, “Elements of Fiction Writing – Characters & Viewpoint” – This is one of those classic texts that I was told I needed. I am still reading it so “no comment” at this time.