Characteristics that appeal to many book groups:
A moral crisis - did the character make the right decision?
Ambiguous endings and plot twists.
Books with wide appeal - think about the Nancy Pearl appeal elements of story, setting, language and character.
Points to consider:
Is the book readily discussable? What will the book group talk about?
How long is the book? Do your group members have enough time to invest in a book that is 300+ pages long?
What is the tone of the book?
Can book groups suggest titles for purchase?
Aim for a variety of titles in fiction and non-fiction? Consider short stories and poetry as part of the mix.
Buy books with the largest print you can. Trade paperbacks are ideal. Consider ebooks.
Consider if the title is available as large print, audiobook, or film - this may be important for some groups
Will enough of your book groups want to read this book to make it a worthwhile investment?
If you are looking to start a reading group, have a look at the book club lists from other libraries:
Riverina Regional Library
Warringah Library
Wingecarribee Public Library
Clarence Regional Library