I was pretty disappointed by this book. Essentially it only repeats a single piece of advice: make a schedule when and stick to it. This advice is repeated over and over in the book with slightly different themes.
The book contains some nice debunking of common myths why writing is hard (again leading to the conclusion that yes it is hard, but it can be done if you stick to a schedule).
It also contains some notes on style (which I did not expect and which do not really fit to the theme of the book), but those are rather superficial; there are much better books dedicated to this. It is also pretty much fixed on writing for psychology (which is not obvious from the cover), e.g., he constantly refers to the APA guidelines, so several tips do not apply to other domains.
When you really struggle to write at all, the repeated advice how to set up a schedule and stick to it might help. For all others, there is not much to it from my perspective.