I think he did extremely well, in the book frodo is described as being fairer than most, with a slight cleft in his chin, Elijah was perfect for this role! And his accent is so believable . I amor ya Elijah ! Xxx
I think that Elijah acted out Frodo well, especially the innocence. There is something about Frodo that is clean, as if he hasn't seen too much evil yet, that his opinions are mais honest and true than the opinions of the warriors in the story. Frodo seems to have the coração of a child; he does not judge and he isn't selfish. I think that Elijah acted out that part really well. I can't think of any other actor as Frodo except Elijah.
