DISCLAIMER: I'm not promoting these books or websites, just passing along what I hope is helpful information. I make no profit on any of them, nor do I guarantee they will help you as much as they helped me. The links were valid when I created this page. If one's broken, please let me know.
Plotting
This book helped me better understanding plotting. It taught me the three act, 15-beat structure to shape a story. While reading it, I substituted "novel" for "screenplay" and the information made perfect sense.
The Writer's Journey: Mythic Structure for Writers by Christopher Vogler
As much as Save the Cat helped me, The Writer's Journey made everything much clearer. It breaks down each beat into parts and explains how to use them to make your writing better. This book has become my primary writing guide. I keep a copy of it at my desk at all times.
How to Write a Damn Good Mystery by James N. Frey
This book helped me to better understand outlining and pre-planning a plot.
Character Development
This book helped me to move beyond one-dimensional
characters by teaching me how to give every character a goal and a motivation
that builds conflict. Highly recommended.
Self-Editing
The Book on Writing: The Ultimate Guide to Writing Well by Paula
LaRocque(Disclaimer: I know this author personally) but that doesn't lessen the impact of the book. Slanted more toward non-fiction writers, the book still gives novelist some profound instruction on writing clean prose.
Thanks, But This Isn't For Us: A (Sort of) Compassionate Guide to Why Your Writing is Being Rejected by Jessica Page Morrell
This one kicked me in the gut with its blunt honesty, but I found myself repeatedly wondering: "I don't do that, do I?"
Written by a literary agent, this book is some good information that every writer should follow.
Self-Editing for Fiction Writers: How to Edit Yourself into Print
by Renni Browne and Dave King
I have met an endless number of fellow writers who rave
about this book. I found it helpful, but not worth raving about. However, I
include it, because the information is beneficial.
World Building
The Writer's Guide to Creating a Science Fiction Universe by George
Ochoa and Jeffrey OsierI stumbled across this one and have found it to be a refreshing how-to book that not only educates but also illuminates. Worth reading if you write SF&F.
Preditors & Editors
This website is an invaluable resource that helps writers sort out the con-artists from the legitimate literary agents. While the webpage is a little old fashioned and sometimes difficult to navigate, the information it contains is priceless.
Markets
RalanA great source for markets for your work. Yes, it's for us SF&F writers. Sorry, I can't help with other genres.