Like Treehouse said, the white needs to build up from a darker tone like a "bone" color. Painting straight clean white will look abnormal. Also the red and the black could use some more highlights. But for a beginner you´re very good!
Give the book some letters... not actually real letters but shaky doodle lines in black... (hopefully this makes sense in english)
Start with a capital letter in the upper left corner like in old bibles or medieval books. That will improve the book by far.