Your best ideas won't come from staring harder at a problem, they'll come from immersing yourself in the ideas and thoughts of others. The best way to do this is by immersing yourself in great books. However, each book you read deserves a different amount of your finite resources.
Here's a "5 pack" of brilliant books for creatives that will help you do brilliant work. Each deals with a different aspect of creative and organizational life, but is relevant and immediately applicable to anyone trying to thrive in the create-on-demand world.