Recommendations here or at Goodreads or on Amazon attract my attention, and if a book sounds tempting enough I'll download a sample.
Reading a substantial sample is the best way I know of to determine whether the book is really what I am looking for, since recommendations by themselves, even from people whose opinions I respect, are not as reliable. The same goes for reviews and ratings. Even when there is some similarity in interests and tastes, opinions of any given book may differ so greatly. Plus, since the sample is free, I can take a chance on books that I might otherwise have passed by.
I'll also try a lot of books on KU. (This takes the place of browsing the "New Books" shelves at the public library, which I used to do every couple of weeks, and take home an armload of books, back when printed matter was not so hard on my eyes. Thank goodness for adjustable font sizes in ebooks.)