Watch how bookstores appeal to impulse purchases: end caps with hot new titles. Displays scattered throughout the store. Shelf talkers. And now the cash register receipt lists "if you liked this book, buy these titles." How does this work in a library?
End caps might not be practical. However, we can use spinners to highlight books. We can print signs like PARANORMAL ROMANCE or IT SEEMED LIKE A GOOD IDEA AT THE TIME OR BLOODTHIRSTY. We can set up displays on top of shelves, counters, and tables. Not just displays to celebrate fall, holidays, etc. But displays that include "oldies but goodies," or "new arrivals," or even "banned books." Shelf talkers can be as simple as an index card taped to a shelf highlighting one title. Books turned out so we see more than spines works (and I secretly turn out titles in bookstores hoping a wandering teen will discover a book by something other than a spine). A box of books by the check out station might work, too.
I know many of you are using these and other techniques. If you are in a place where this is not happening, volunteer to do these little things for the school or public library. Catch readers where they are. Count on impulse to lead them to a book or two.