To be honest, I don't often remember how I find books.
I found "The Hobbit" from a bargain bin of adult audio books - when I was around 10 years of age. And no, I never normally listen to audio books, and it took a lot of convincing to get my mother to buy it - it was in a adult audio book bin after all!
No idea what drew me to it even today. This was many years before the movies were even contemplated.
It took a long time to get a copy in paperback (one of the tapes wore out in the interim), and many years before I got The Lord of the Rings (as a gift; much begging was needed). I don't know how I found out about tLotR - not from the movies, certainly.
Nowadays I accept recommendations from individuals, media, accidental findings, books on a theme and general good luck. There is no #1 method.