Social media (goodreads/tiktok/reddit)? Colleagues? Friends? Browsing the library/bookstore? Asking for recommendations from staff at libraries/bookstores?
BONUS: if you can remember, how did you find books you really enjoyed?
I realized a lot of my favorite book recs came from reddit. I was a subscriber of r/books and picked up some really good books there. Piranesi by Susanna Clarke is an example.
Podcasts are my biggest source for recommendations. That and if I find a movie or show I like, I look up the source material or related books in the same universe.