Develop a hook. Crime caper hooks require the heroes to tackle an extraordinary (if not impossible) heist: a bank vault with state or the art security, an impregnable fortress or a top-secret facility. Dreaming up a caper isn't enough; you also have to figure out how your heroes will succeed.
Research the caper. Crime capers depend on believability: the reader has to sense that the crime is really difficult but the solution possible. This means reading up on safes, security systems, weapons and escape vehicles.
Create your characters. Crime caper heroes are rarely good guys--they can be ex-cons, ex cops, down on their luck smugglers, former security experts fired for a past infraction--but they must be likable. If your audience can't root for them, they probably won't care. Don't forget your supporting characters: the love interest (who usually no longer trusts the hero), the partners in crime, and the villain (usually a crooked cop, a former employer or a buy-the-book investigator determined to stop the crime).
Plan your escape. The entire third act of a crime caper occurs after the crime is committed. You can create an exciting car chase with explosions or a cat-and-mouse game of subterfuge.
Write an outline in three acts. Act one should set up the crime; introduce the viewer to the target and explain why the hero must take it down. Act two should plot the caper itself and end with the successful heist. Act three should be the getaway, and should involve the loudest explosions or most suspenseful confrontations.
Finish your screenplay. Throw in a few complications and plot twists to keep things interesting. Keep track of movie time, usually a minute per page. Good crime capers should wrap up under 2 hours (90 to 120 pages).