A script, be it adaptation or original, is more than converting
a novel (or a novelist's techniques) into screenplay form. Film is a visual medium; everything you tell in a book you have
to show in a screenplay through action. Unlike a novel, which can be as long as you like, most movie scripts are limited from
110 to 120 pages, one-hour teleplays to 70 pages. A novel can digress, but for a script to work, your story has to be tight.
Each scene must further character or plot or, preferably, both at the same time.
In a script, the dialogue has to
be entertaining. It has to move fast. Each word must become a lean, mean, verbal bullet. Exposition and plot points (which
could take several pages in a novel) need to be tight and to the point. There should be nothing extraneous, nothing wasted
on non-essential dialogue, action or description.