For the target audience of elementary and middle school kids, this is a good book with all the basics - lots of concrete ideas for the writing process, lots of examples from Fletcher and other appropriate authors. For me as an adult reading for the usefulness to a high school English class, it seems a little bland and boring, watered down, and casual, but still hammering on the things high school students have already heard for a decade.
Also, probably thanks to the colorful and nicely illustrated cover, I expected some illustration inside, even if it was just a few little doodles with the end of each chapter. But there is nothing. It's fine, since art is not usually Fletcher's medium, but I felt like the cover was a little misleading.
All in all, I was thinking about reading his other three books of writing advice, but I suspect they will be in a similar vein to this one and I can skip them.