I'm interested in learning to write better reviews than I do, now. Does anyone have any sources they'd share on the topic? I've never done any kind of education on the topic, so I won't be insulted by suggestions for very basic topics. I might not use them, but I won't be insulted by them.
Well, like all things writing, practice is a good way of doing it better! This might give you a few pointers for critique -- https://www.writingforums.org/threads/constructive-critiques.20627/
Read good, preferably long and in-depth reviews. Also look into literary theory, there's a number of different approaches to a book you can take - the best books have something you could take for every perspective, I think. If you are talking about reviews, there's some decent ones on Goodreads, in papers like the New York Book Review. Theory is important there. An example of theory can be post colonial theory, the hidden grimness of Jane Austen novels where in, the example I'm thinking of, Mansfield Hall the family money is made on sugar plantations in the colonies and slavery. It's a little throw away line in the actual text, but if you remember that as you read the novel - they are wealthy because of slavery, the novel takes on a whole other feel and meaning. Really it depends on how deep you actually want to go into things. Reading good reviews is important. More important. A bad book is often just boring, a bad review can be utter nonsense - or worse. If you're just talking about critiques, just read a lot and develop your taste.
As a writer, I want to know. Did the story interest you? Did it flow and make sense to you? Did you find a spot where you lost interest? Is there a spot where you were confused? Is the premise believable? Is the dialog working for the characters? Did the ending work, is there enough of a hook? Spelling and grammar. Most writers seem to forget they're telling a story. I use the analogy, if you were reading your work at a party would anyone stop to ease drop in on what you were saying?