Those who read the books know that the movie will be adding more "visions" of Robert Pattinson as Edward Cullen, something that does not happen in the original story. In these "vision" sequences, Edward will wearing the same outfit he does when he leaves Bella, played by Kristen Stewart, in the woods because that is the last memory she has of him.
One very special visual effect that will be found in the movie is conveying the passage of time in which Bella is depressed. In the book, several chapters are simply the title of months, suggesting that nothing has changed while Bella is in turmoil.
In the film the passage of time is represented with Bella sitting in her chair in her room while a camera circles around here and the seasons change outside her window. Also, during the beginning parts of the film both will be dressing alike, or rather, Bella's wardrobe is linked to Edwards as a sign of her commitment to him.
Once he leaves, she doesn't pay much attention to her appearance. Finally, one scene not found in the book but added to the move is a scene in which Jacob, played by Taylor Lautner, gives Bella a dream catcher to send away her bad dreams.
The prop is used to convey some heavy emotions in the movie. On the one had, Edward is annoyed that his rival gives such a personal gift to Bella, while Bella's father Charlie is saddened when it stops working after Edward disappears.