First the book sings the praises of doing zentangle for the experience itself, regardless of the finished product. Then the rest of the book is spent suggesting ways to make more appealing finished pieces.
Also maddening - the book tells us that shading is vital to several of the included zentangle patterns, but gives no instruction on how to do shading.
It's a nice collection of ideas if you're already somewhat familiar with zentangle, or with basic drawing.