Eight options are provided :
- Recommend the book that you last read
- Recommend the latest bestseller
- Ask what author they like best
- Point out the display of new books
- Ask what kind of read they prefer
- Tell them they will find something good in the new promotion
- Give them something from returned today (trolley)
- Ask the next person in the queue what they would recommend
Generally you would begin by asking them about the type of books they prefer to read but after that there would be a variety of options depending on their response.
If the initial response is, for example, crime books then it would be logical to ask about the authors they prefer to read and then suggest authors who write similar books. Showing a borrower how to use Library Thing via the library catalogue may help them to explore the books of other authors. Who else writes like ...? (in print form or online version) may also be a useful tool.
It could well be that there is a promotional display of books in the library that may be relevant in which case you could suggest that they might like to look at some of the books in the display. However if the display was of romance novels it is unlikely that a reader of crime would be interested.
New book displays and recently returned trolleys provide good browsing points for readers looking for something different to read if they are prepared to browse.
Asking the next person in the queue what they would recommend is problematic as the likelihood of the readers having similar tastes is not great and if there is a queue you want to move things along as quickly as possible. Recommending the book that you last read might work only if the book was similar to the tsaste of the reader.
The reader may already have read most of the books by an author or group of authors who write similar books so it would be necessary to establish what they like about books written by the author(s) and then try to find a different book that they might like to read.
Authors of books, of course, do not not always stick to one genre. Ken Follett, for example, is known for writing contemporary suspense fiction however in 1986 he wrote a book set in medieval England - Pillars of the Earth - which introduced him to a wider / different audience. The works of some authors are hard to categorise for example the Outlander series of books of Diana Gabaldon - are they fantasy, historical fiction, romance? - they contain all three elements.
Genres may contain many subcategories. Which subcategory does the author prefer? It may be possible to suggest books with similar subcategories in a different genre. If they enjoy historical romances is it the romance that primarily attracts them or the historical aspects of the books? If the reader likes suspence crime they may like to try an adventure or even a science fiction book. Humour is a component of many books and a reader of humourous crime books may decide to try a humourous fantasy or science fiction book. Readers of fiction may also be encourage to try books in the non-fiction section on a topic that formed part of a novel.
In short there would appear to be no simple answer to this question apart from working with the reader to explore other options that would hopefully lead them to discovering other good books to read.