No one picks up a camera and becomes automatically a good photographer. Everyone starts off bad or mediocre. Photography is a skill that can only be learned and improved upon through the act of doing it.
If your first instinct as a beginner photographer is to pick up a photography book and learn about its rules and theories, and you think that’s going to make you become a good photographer, you’re going down a somewhat misguided path. All the abstract talk and writing about photography is useful—just as this book might be useful—but they are only an aid to your learning journey as a photographer. Nothing can help you learn as much as the actual, simple act of taking a photo with your camera.
Photography theory is only photography theory—don’t confuse it with photography.