The role of the writer LOR

Making larger roles for the female characters in the film.

arwens character was just a little poem at the end of the book then she becomes a major role in the film  

Taking out (omitting) certain characters in the film look at this site for help.

they took out tom and his character was the only one who could resist the ring

Writing an exposition (what has happened before the film starts) scene for the beginning of the film. in the film Gandalf talks about the past and Gimli talks about his past about the dwarfs  

Working with the actors as characters to create some parts of the script. 

they would sit down with the actors and ask the question and they would answer as if they were the character