I was never into self help type books. And this book is not that but along those lines. Basically put in the work and time and your art (content) will get better. Its a light read but keeps me focused every now and then when I need to get my priorities straight and concentrate on what I need to get done.

http://www.stevenpressfield.com/the-war-of-art/

Or if you are into philosophy. This is the same only different. :)