Talk a different set of books for each class so no single book is so much in demand that you can't fulfill student requests to read it reasonably soon. Try to have two or three copies of the books you talk. Hot themes for booktalks include dogs, courage, the ocean, and voyages to other planets. A hook for classics is telling kids that those books are for the mature reader who is ready to meet the challenge of more difficult and complex subjects. Just don't use the word classic.
Teachers say that's the kiss of death.
Assemble several books, half nonfiction and half fiction. Present each booktalk in journalistic style, and remember that sharing enticing facts holds kids' interest best. Raffle off the books at the end of the booktalk. Remember to ask your group whether anyone has read the book you're talking. Kids are more likely to accept recommendations from their peers.