An explanation for my ratings system can actually (currently) be seen in the right-hand sidebar of Amara's Eden. It is also explained in a more in-depth nature on my Review Policy page. But here's the gist of it.
If I've rated a book one star, that means I didn't enjoy the book at all. It wasn't just mediocre; it was unpleasant, offensive, disappointing, or just plain boring. What exactly earned the book's single-star rating can vary. Perhaps the plot was nonsensical, the characters were aggravating, the themes of the story were upsetting (and not in an intentional, thought-provoking way), or the writing and/or editing was beneath my standards. One particularly poor category here can ruin my opinion of a book, unless there's some other particularly well-done aspect to make up for it.
Some examples of one star reviews here at Amara's Eden include Everneath by Brodi Ashton, which bored me to the point that I decided to DNF, and The Terrorist by Caroline B. Cooney, which featured an insufferable and racist main character.
Two star books are books that didn't disappoint me, exactly... but they didn't impress me, either. They just didn't garner a particular emotional response, and all in all, they came across to me personally as mediocre, and they don't particularly inspire me to read the next book(s) in the series or look for more of the author's work. But I certainly won't swear off doing so, either.
Examples of two star reviews here at Amara's Eden include Meet Kirsten: An American Girl by Janet Beeler Shaw, which was a bit of a strange bird in the American Girl series, and Chu's Day by Neil Gaiman, which was cute but not exactly what I expect from a Gaiman story.
A lot of the picture books I read tend to fall into this category.
Three stars is where things start getting good. Any book that earns three stars from me is a book that I can safely say I enjoyed. It might not be something I'm going to come back to, but it was something that I finished reading with a feeling of satisfaction. Either the characters appealed to me, the plot was entertaining, the writing style was impressive, or some other factor made it a fun way to spend a few hours (or minutes, if it was a picture book) of my life. Three star books are the kinds of books that I'll plan on eventually picking up the sequel to, and they're the kind that inspire me to read more from the author.
Some examples of three star reviews I've written are The Secret of the Old Clock by Carolyn Keene, which is a classic Nancy Drew story I've enjoyed since childhood, and Mustache Baby by Bridget Heos, which was a picture book with some truly adorable art.
The three star category tends to house most of my revisited childhood reads.
Four stars is much rarer than three, but far from unheard of. Four star books are books that I enjoyed and feel qualify as "above average" in some way. Maybe I loved the world-building or the story had an emotional impact on me. Whatever the reason, four star books are enjoyable, like three star books, but not quite at the five star level--but they have the potential to get there upon rereading, and four star books have a pretty good chance of being revisited one day.
Some examples of four star books are The Truth about Bats by Eva Moore, which was a childhood favorite of mine, and The Ultra-Violets by Sophie Bell, which was a really adorable and charming story with awesome art.
Five star books are potential new favorites. These books truly wowed me in some way, whether by telling an amazing story, building an amazing world, or emotionally impacting me in a genuine, intense way. These are books that I will almost certainly reread eventually--with the possible exception of nonfiction--and have a pretty good chance of moving up to the gold star category one day.
Examples include Into Great Silence: A Memoir of Discovery and Loss Among Vanishing Orcas by Eva Saulitis, which was an environmentalist memoir that struck me an emotional chord with me toward the end, and To Kill a Mockingbird by Harper Lee, which is one of the few classics I've read that I feel truly deserves its reputation.
Gold star books are alternately referred to as favorites. These are books that I'll recommend to anyone and everyone looking for something to read. They're books that I'll go back to over and over again, rereading obsessively even when I should be reading something else. They're books that held nurture or define my love of reading, and they're books that have made a lasting impact on me in some fashion. A lot of these are childhood favorites, but that should start changing as I become a more active reader in my adulthood (after a slump in my adolescence).
Examples include The Bad Beginning (A Series of Unfortunate Events, #1) by Lemony Snicket, which is a late childhood favorite of mine, and The Absent Author (A to Z Mysteries, #1) by Ron Roy, which is perhaps the first series I truly fell in love with.
On websites like Leafmarks, BookLikes, and Goodreads, of course, there are no gold stars, so these books get mixed in with five stars on those platforms.
As you can see, the vast majority of books I read fall in the two to three star range, and the four and one star categories around almost even. So, given that three is enjoyable and my current GR average is 2.79 stars, I'd say my rating system is fairly on point. Most things are indeed good (three stars) or average (two stars), with bad (one), great (four), and awesome/favorite (five) being outliers.
So what about you: how do you rate? Do you wind up with an average rating far above or below your star rating that actually means average? Or you a reviewer who tends to give mostly four and five star ratings or never gives out one star ratings? Or do you tend to give out mostly low star ratings and no high ones? Let me know in the comments below!