"Prepare to Board" covers most pre-production aspects of an animation project, but focuses mostly on storyboarding and character design. This book does a better job on both these subjects than most other books can manage on just one.
A lot of storyboarding books out there focus on the live action or advertising methods where boards are used to illustrate an existing script a sell a rough concept to non-creative executives. The methods Nancy Beiman shows are far better suited to animation's use of storyboards to create the story itself.
Along with guidelines on how to increase the cinematic storytelling power of your boards, there are also plenty of tips on how to get that power across when presenting boards to others.
When it comes to character design, "Prepare to Board" is up there with Tom Bancroft's "Creating Characters with Personality: For Film, TV, Animation, Video Games, and Graphic Novels" as one of the few indispensable resources on the subject. All of her advice is aimed at making your character designs more functional for animation & storytelling (the most important asset of any character) as well as being unique individuals rather than stock characters.
The lessons Beiman shares in this book are exactly what you need to build a strong foundation for any animated project.