Amazon will delete spam reviews if they are reported. Reviewers and reviews get meta-reviewed, and poorly meta-reviewed reviews won't appear in the featured reviews for your book.
BUT that means you still need a critical mass of genuine reviewers who give your book positive reviews, and for technical books, sometimes that's hard to come by. One way to do this is to get lots of people reviewing your manuscript pre-publication. That has lots of other obvious benefits, too.
Reply to reviews, especially if a reader had difficulty with a code example and you can help them.
BUT that means you still need a critical mass of genuine reviewers who give your book positive reviews, and for technical books, sometimes that's hard to come by. One way to do this is to get lots of people reviewing your manuscript pre-publication. That has lots of other obvious benefits, too.
Reply to reviews, especially if a reader had difficulty with a code example and you can help them.