Bookstores, Locus, friends (word-of-mouth and blogs), my favorite mail-order bookstore's (Mark V. Ziesing Books) print catalog (!). When I attended more sf/f/h conventions I'd go to panels and would often get books by authors who said interesting things.

(On the flip side, I stopped reading/getting books/vowed not to buy books by some authors who irritated/appalled me by their comments.)