I have a bunch of authors that I really like, so I’ll read practically anything written by them.
When you order books on Amazon, other suggestions pop up that other people, who have liked the book you are buying, also liked. You can go down a deep rabbit hole that way, and find all sorts of things that you otherwise might not have known about.
Also, our farmers market has a free lending library, in which you can take, or donate, as many books as you want. You don’t have to bring them back, although I usually do, and just swap them out for different books. I take all of the books I’ve purchased to this book exchange. I’ve found some wonderful things there.
With movies, I watch a lot of stuff on Netflix, and you can set up your profile (and rate movies you’ve seen) to get suggestions for othet movies you might like. I also enjoy reading the reviews on this site. Sometimes a well written review will be the thing that makes me to decide to choose a particular movie, that I might not have chosen if I had not read that specific review.
As far as movies at the theater, I either see trailers on TV, or at the theater when I’m watching another movie. I know what types of movies I like, and which genres I don’t like.
Sometimes my friends and relatives will reccommend a book or movie.
I also read reviews in our local paper, and entertainment publications.