Many screenplays and, as a result, motion pictures often fail right from the start at the plotting stage. Granted, creating a plot outline may not seem like a lot of fun for some writers when compared to creating jokes, snappy character dialogue, and heart-pounding special effects-laden action sequences; but, without a foundation a structure will collapse - like a house of cards, literally and figuratively.
Literally, many screenwriters use index cards as a common technique for structuring a plot outline. This method simply described: during the first draft of the plot structure, each scene or sequence within a screenplay is given its own index card.
A deck can be easily shuffled; cards can be tossed out; and new cards can be added to the deck. As a result, plotting becomes a fluid process closely akin to the intuitive way the creative mind works. It becomes as much fun as creating jokes, dialogue zingers, and blockbuster action scenes.
Find a quiet place to write. Have a deck of index cards and a writing instrument nearby. Play your screenplay story in your head, over and over if necessary.
As you see a scene or plot sequence unfold, write a description on an index card. The description should be key words at minimum, one or two sentences at maximum. While brevity is necessary in each part of a plot outline, at the first draft stage of this technique, it's okay to wind up with as many plotting cards in your deck as you desire. At the first draft of a plot outline, the looser you are the better the results. You can always toss out cards in subsequent drafts.
Once you reach a point where you're satisfied with the structure that you've created, spread all the cards in the deck across a table for an immediate visual assessment of your screenplay's timing and scene interaction. If you don't like the results, reassemble the deck and revise as needed.
Once you feel satisfied with the table assessment, start writing scenes. Don't throw your deck of cards away because, rewriting is a natural part of the writing process, and you may have to go back to your deck to reshuffle and revise your plot structure.