After you outline the film you go out to shoot all the footage you are going to need for the final draft of the film. You can’t produce a film without all the footage. Think of your writing projects in the same fashion. Write your first draft by getting all the possible ideas out of your head before you go back to start editing. Just as the filmmakers needs to shoot all the footage before editing, you need to get all the words onto paper. You can actually produce meaningful work when you shoot all the footage first.