At the top of each review, I rate books on a scale of 0-5 stars based on how much I like the book and what I perceive as its literary merit. Here's how to interpret those ratings:
0 Stars: I disliked this book so much I couldn't finish it.
1 Star: I did not like this book, and I don't think it's very good.
2 Stars: I did not like this book much, but in literary terms I think it's okay. Or, the things I disliked about this book undermine what I perceive as its literary merits to the degree that I can't give it a higher rating.
3 Stars: I liked this book but didn't love it, and it's at least acceptable in terms of quality. I'd recommend it if you like this kind of thing ("this kind of thing" being the genre, style, series, type of main character, etc.).
4 Stars: I really liked this book and would heartily recommend it.
5 Stars: I loved this book so much that I don't care whether it's "good" or not, but it probably is. Also, you should read it. Now.