★ - dislike; I shouldn’t have wasted my time
★★ - ok, but just barely; flawed but not a total waste of time
★★★ - liked it, but pretty average; not a book with a major impact on me
★★★★ - liked it a lot; will definitely recommend to others
★★★★★ - loved it; among the best I’ve ever read
I also give half stars to bump a book up if I think it is better than the star level indicated but not good enough to be bumped to the next star level
For more details on my ratings, refer to this post and this post.