I typically rate my books on a 5 Star rating system, thanks to Goodreads.
So below is how I typically classify each category:
★★★★★ - FANTASTIC. I want to read it again and again!
★★★★☆ - Really, really good book! Loved it.
★★★☆☆ - Enjoyed it, it was average
★★☆☆☆ - Didn't hate it, but didn't really like it either
★☆☆☆☆ - Didn't like it, not at all. Pretty much hated it.
☆☆☆☆☆ - DNF
I am pretty lenient with my ratings because I am easy to please so it’s very, very rare that I give a book a one star rating, however it does happen. I usually slide between two ratings as well, but I’ll always explain if that happens.