Students often choose books to read based on the recommendation of their peers. A book talk is a brief overview of a book designed to raise the interest of potential readers. In many ways, it is a sales pitch for the book given by someone who has read it.
I would model a book share by creating a brief presentation that includes the title, author and a brief summary. Use language to persuade others to read the book. State why you like the book and why others should read it.
Students could then go back and listen to other book recommendations when deciding which book to read next.