First, I follow the “schoolmarm” method in my initial evaluation of a book considered for review:
Did the author follow the instructions?
Did he or she submit a synopsis? Is the synopsis succinct or is it longer than the book?
Is the request intelligible?
Is the grammar correct?
Is the syntax correct?
Despite the fact that the Chicago Manual of Style and the AP Style book changed its recommendations about the singular “they” in March of 2017, that usage still jars me out of the content of the synopsis or story.
Second, if a request is clearly software “bot” generated, I politely eschew further consideration, especially when the request begins with “Hey” or “Hi” or has a blank where my name should be, or uses a generic name, or uses the wrong name.
Third, if a request is sent by an agent or third-party, I usually decline. But how the book was published is irrelevant to me.
For e-books, in my opinion, the cover is almost incidental, except to the extent that I will avoid any book with a studiously hackneyed cover, common to many of the “romance” novels. In fact, if an author has spent a lot of money on a cover, for an electronic book, I am suspicious that he or she is covering up bad writing.
I avoid nonsensical “works” masquerading as avant-garde masterpieces. I also avoid specious premises, which eliminates many of the “dystopian science fiction” requests I receive. Usually those books are fiction, minus any science.
I avoid “plug and play” books which, though well-written, obviously follow a formula and “plug in” characters or places. This usually applies to series.
I usually send each author a list of issues with spelling and grammar, which requires an hour or two. If the author agrees to update his or her book, then I continue with the review. Otherwise, I move on. Of late, I have received many books, allegedly edited by one or more editors, containing egregious obvious errors. As noted before, my objection to these errors is not simply an academic exercise, one is booted out of the narrative by those errors, assuming one went to school when such things mattered.
Once I start to read, I look for internal consistency; a good plot or a narrative in the case of books where “nothing happens”; well-developed characters; philosophical insights; psychological insights; and homonyms used incorrectly. I also look for breath-taking prose in “literary” novels. The use of inordinate amounts of “trendy” cultural references bothers me, except where the intent is satirical or germane to a pop-culture subject.
I look for a table of contents that is functional. If I want to return to a particular “location” I need a table of contents rather than the location number supplied by an e-reader.
In nonfiction books, I look for jargon or peculiar usages which are not adequately explained and create a barrier between the author and the reader. If I find jargon, I send a polite email explaining why I will not continue the review.
I look for specious elements. If I cannot give a book at least four stars, I do not post a review. Perhaps it would be useful for reviewers to list all of the books read for consideration at the bottom of our “blogs.” That list could then be compared with the books which warranted reviews.