I'm sure this has been done before, but who cares?
Hero/heroine has a special horse, which could basically be described as "Like Shadowfax, only much, much better". –take a shot.
Hero/Heroine owns an improbable number of extra-special weapons. –take a shot.
Heroine dresses in black leather. –take a shot.
Hero/Heroine is mentioned in a badly-rhymed Ancient Prophecy. –take two shots.
Hero/Heroine has a special connection to the Ring. –take two shots.
Hero/heroine is allowed to join the Fellowship despite being a vampire/werewolf/half-orc/Sauron's kid/something else which has no business being there. –take two shots.
Hero/heroine is a fairy/angel*/merperson/something else which has no business being in Middle-earth at all. –take
three shots.
Legolas and Aragorn are old friends and have adventures together, most of which consist of being captured and tortured by random bad guys. –take a shot.
Aragorn or Legolas is deaf/blind/mute/scarred/paralysed. –take two shots.
The Council of Elrond scene from the movie is quoted verbatim. –take a shot.
The fic's premise means that the actual plot of LotR couldn't happen at all. –take three shots.
*Note: meaning traditional angel, with wings, not Ainu.