Planning my first  book is a very adjustable worksheet. Younger students can plan their fist book by using only pictures, while older students can use drawings and writing. The planning includes the characters, settings and the sequence of the book: beginning, middle and end. I'm having my students plan their fist book in pairs, so they can have some team work! And of course this requires a lot of monitoring from the teacher.
The idea is that after the planning, they can start creating their books.