>>24529856 (OP)Start with something small and centered on a genre you have interest in with other media.
Scifi? Neuromancer or Dune, I guess. I don't read much science fiction.
Horror? Lovecraft or Clive Barker, maybe a King if you're feeling frisky and have the time to sort through the books that aren't really worth reading.
Fantasy? Conan or Tolkien, fuck it, throw Percy Jackson in there.
Point is you've gotta build your focus up like any other skill. Set like, 30 minutes aside a day to turn all your screens off and read and work from there. Reduce the time if it helps.