The least effective and worst method I tried for getting reviews through Goodreads was the general reading review groups. There are some review groups sorted by genre, I am not talking about those. Those actually got me the best number of reviews that had the best quality.
In the General review group, you don't have any say in what genre or book you are going to be reviewing. This is a tragedy.
A review group already has a few marks against it because you are meeting with other desperate authors--it stinks to give a poor review but not everyone is an author and even authors need good editors (or at least good beta readers) in order to write well. A good author will be constantly reading books in the genre in which they write--I met indie writers who did not read--at all. You have no way of knowing whether the person you review is a good author or not. This means you may get a book that doesn't even make sense, and you must review it, which puts you in the uncomfortable position of how to be honest in a kind way.
Many people would not have a problem letting someone know that there are problems with their books. However, these same people who do not know how to write may be leaving a review for your work--and they think their books are great. Let me put it more bluntly: would you want a doctor working on you if he had never gone to medical school, never studied under another physician, and never read any medical literature? I am not trying to discourage anyone from writing, but if you want to write, you must read. If you don't want to (or can't afford) college, you must surround yourself with college educated editors who will give you constructive feedback. And finally, you must be prepared to accept that feedback. Some people in the review group will not accept feedback gracefully and some people in the review group might not be able to tell what a good book is like. But if you know nothing about books, you should not be reviewing an indie book. This hurts the indie writers who do know what they are doing and who may have even put money into the book by paying editors or proofreaders.
These are general problems with any review groups. When you join a general review group, the problems are compounded. In a general review group, you may have one person who reads and writes non-fiction dog books, one person who writes erotica, a children's book writer, and one person who writes epic science fiction. A person who has submitted a 20 page children's book for review will not want to read a 1200 page epic sci-fi novel. So, once he finds out the book they must review is 1200 pages long, he already hates it without even turning to the first page.
Now, say the dog person gets the erotica. The dog person signed up for the group knowing full well that he might get erotica because it is a general group, but now that he must actually read it he has decided it goes against his religious sensibilities. But the dog person will get disciplinary action if he doesn't write a review. He made it to page 4 before becoming completely disgusted, so that is what the review will be based on (the first four pages) as well as his dislike of the genre.
On the other hand, the lady who wrote the sci-fi tome gets the dog book. The lady thinks dogs are cute and fluffy, but by page 40 she begins to wonder how anyone could write more than 10 pages about dogs little less read about them. She perseveres and finishes the book and gives it 4 out of 5 stars because she gets that some people might like it. Her written review ends up being: "This was a great book about dogs. I highly recommend it." Not necessarily the kind of review that is going to get much notice.
Finally, the guy who writes erotica gets the children's book to review. He doesn't have kids. He doesn't even remember ever reading a children's book except maybe "The Cat in the Hat." He doesn't care because the book is only 20 pages long- it will be a breeze to run through. But it doesn't rhyme. Since he only has one other kids book to compare to, he begins a three paragraph critique on how this book is not a good children's book because it doesn't rhyme. He says nothing about the plot, nothing about how children responded to it (ideally all children's books should be read to children and their reactions judged before giving a review), and absolutely nothing about the adorable pictures that the author paid thousands of dollars to get so it would have a professional look.
Some review groups will have people who skimp out on their job. That means after reading someone's 1200 page tome and writing a review just so your 20 page children's book will get one, you might not get any review at all. I did not have this problem, but it has become such a problem recently that some groups are asking for alternate reviewers--people who like to review books but don't necessarily have one of their own to submit. I did, however, get several reviews that were in the above categories--didn't know anything about the subject so couldn't really tell if it was a good book or not, didn't read the whole book, wasn't familiar with the genre and therefore had no clue that the things they were complaining about in their review were standard for it, and were just angry they had to read your book when theirs wasn't that long. For me, the general review group was completely useless.
