Let's take things one at a time...
What if your considering the possibility of sequels or already have a preplanned story line that spans more than one movie? Like forshadowing for a future sequel.
Well, when you make enough money to finance your own movies,
like George Lucas, you can make exactly what you want and write it any way you please. As of now, though, as I understand it, sequels are only planned
after a movie
makes a s***load of money proves to be popular and successful.
I'm working on a script right now and the main character is plagued by dreams. The dreams are intended to be forshadowing but also reflect the actual scenes that won't take place till about the third film in a trilogy. Or is it best to write it as if it were a standalone piece?
My opinion? Write the things as standalone pieces, but make sure you have hooks - maybe just a throwaway line, or a piece of seemingly irrelevant exposition - that ties in to the later action.
I don't want to sound discouraging, but sequels are not usually writer-driven.
Al B.
"The worst movie in a series is usually Number Six of a trilogy."