Wait 2 years, which is how long it often takes for 2+ scholarly book reviews to show up in different journals.
And, if the research is fundamentally new, you may have to wait another few years (at least) before the good scholarly criticism comes out.
When I read a book with new and interesting ideas, I usually want to know if there are major flaws that any knowledgeable scholar in the field would point out immediately (Two recent examples are Pinker's "The Better Angels of our Nature", and Harriss's "The Nurture Assumption")
I usually:
One problem is that I end up spending a lot of time reading stuff of no interest - either reviewers explaining the book to people who haven't read it (and sometimes even misrepresenting it's arguments, or framing them in terms of their pet controversy), or bloggers/posters who haven't read the book so go off a summary and come up with arguments that are already well-addressed in it.
So, what tips and strategies do you have for finding solid scholarly criticism ?