What Makes a Great Picture Book? 10 Key Elements

It's almost the end of November, and man has it flown by. Not only did November mark the beginning of our reading period, but it was Picture Book Month. And between all of the talk online about picture books and the huge amount of proposals we've gotten for new children's titles, we've been thinking a lot this month about what makes a great picture book.
After a little digging around online for popular opinions, and examining our own tastes, we've narrowed it down to a list of 10 key elements:

1. The story must understand what it's like to be a child going through something for the first time. "Picture books communicate self-acceptance, and they model coping strategies for children who are just learning to deal with powerful emotions." (Young Children and Picture Books)
2. A picture book should be simple but thoughtful. There is a small amount of space to find the perfect combination where all the elements work perfectly together.
3. The language should fit the audience. It should be playful, be fun, be attention grabbing, but be rich. Never forced. Every word needs to count for something.
4. Picture books are for the adults reading them as well, and so the story should resonate with and be enjoyable for the child AND the adult reading it. There's nothing better than reading a picture book as an adult and having it still mean something to you.