I don't know what to advise you. I started doing reviews several years ago for booksnbytes.com. Then later I did reviews for bestsellersworld.com. Armchair Interviews has a place that you can apply to be a reviewer and bestsellers does too. I think you have to send them a sample but I don't remember that for sure.
I've read and enjoyed Donald Westlake's books. I just did a review for Armchair Interviews on Broken Wing by Thomas Lakeman. The main character works for the FBI. There are two prior books with the same character but I haven't read them.