The shorter the hook, the better. If you can ask the teachers to watch some high-quality 2-minute booktalks online, that would be good preparation so they don't ramble too much. Another great exercise to keep booktalks brief is the 6-Second Summary/Elevator Pitch. Anything longer than 2 minutes and today's kids will have zoned out.
Costumes and/or props are possibilities, of course the more clever and representative of the book, the better. Depending on the book, reading a couple of gripping paragraphs works.
A song that ties in with the book is another idea. I work with high school kids, and love "Love Potion #9" with "A Midsummer Night's Dream" or "Suspicious Minds" with "Othello."
How about telling part of the story with emojis projected on a whiteboard/SmartBoard?
Maybe turn the presentation into a tv news program. You can have some contemporary books as "news," "international news" (set in another country), then a "sports" feature, maybe "weather" (disaster-based thrillers?), a human interest story (SEL), etc.
Have fun with it! The students love to see their teachers being creative.
Cathy Andronik
(Retired, Brien McMahon HS, Norwalk--currently presenting for the Bureau of Education & Researcy)