Hi PhDer
I've done some book reviews in my time - they don't take quite as long as you might think, but they're very easy to keep putting off (!).
I'd set aside some dedicated time and try and get the book read in a few sessions, making notes as you go.
I tend to structure actual reviews as summaries. Introduce the material, then offer a precis of the main arguments on a chapter-by-chapter basis, assessing any strengths or weaknesses as you go. This is helpful for readers as they get a sense of what the book actually covers as well as your appraisal of it. It's also quite easy to organise and write a review this way. You can sign off with a general summary of the book, suggesting who it would be most useful to, what further avenues for inquiry it implies and any significant limitations or potential it has.
Hope that helps a wee bit - happy to try and help answer any more specific questions.
Mark