It’s #140 so you get another long one!
And before anyone tries to eat me, I’m sure some people can cherry-pick times where cold-e-mailing someone who’s expressed no interest in reviewing for you has resulted in a sale or a review. As for me, I specifically state “do not contact me to ask me to review your book, even if it’s free” in my Amazon profile because I hate it so much. You at least want to avoid spamming people who have tried to opt out or whose information is gathered from places that explicitly forbid what you’re doing. For instance, sometimes you see authors commenting on Goodreads reviews of similar books trying to get readers to read theirs, and it’s very much against their policy! Don’t do this!
The secret lies in sharing your work with people who love to be excited about books. People who are there because they want to be. People who have asked for work like yours, or are happy to review it, or will be paid (by you) for their time. It’s very common for unprofessional products to be pushed through unprofessional tactics as well, so if you don’t want possibly interested people to look at your book and think it looks cheap or low quality, GET PROFESSIONALS (or at least other book people) INVOLVED IN VETTING YOUR STUFF. If your book is so important that you’re trying this hard to get it out there, it deserves the best resources you can find!