Literally: find a favorite (not dead) author’s website and use their contact form to send them a message with specifics about why you like them.
I’ve done this several times. The nice thing is they’re usually very accessible and responsive, maybe because they tend not to get the same kind of public praise as actors, musicians, and other more glamorous artists.
Of course this does depend on the author’s level of fame. My favorites tend to be nonfiction writers with an approachable-enough profile to still be accessible by civilians, so if your favorite author is a Cormac McCarthy type then you’re SOL.
You can do this over social media, but a mere “Love your work!” doesn’t have the same effect as a more detailed note, which both proves you’re actually a fan and gives them the fuel to keep going and making more stuff you enjoy.
Anyway, try it sometime.
Comments
Accessibility issues aside, I would only add that one should consider writing thank-you notes to anyone whose work or actions they are thankful for regardless of how responsive they might be. If the true point of writing is to actually thank the person, whether or not they might respond should not matter.
Great idea! In fact, as a book collector who enjoys author-autographed books, I have often written to authors I admire, asking them if I may send them my copy of their book for an autograph. (I provide return shipping materials, as well) This is surprisingly successful, and I’ve collected many autographed books this way.