I type up a schedule for the whole session, which runs from September through June and mail it out in August or pass it out at the September meeting. It includes the book names, authors, meeting dates, times and places. Many authors have their own web sites with biographical information, interviews, editorial comments on their books and more. For older books, you can find books of criticism on the authors and their work. Whenever a fellow reader whose taste you trust recommends a book, jot it down.
Word of mouth is THE best recommendation.
The same goes for people you know in other book groups. Ask which books they've read that have been successful for discussion. After a while you'll figure out how to read between the lines of the book reviews and discern which books your group would enjoy the most. Publishers' web sites often review books, though the recommendations are not always reliable. If you like Oprah's choices, pick those.