A flash forward is an exciting scene or sequence, followed by words like ‘6 Weeks Earlier’, or ’12 Hours Earlier’ or ‘1 Year Ago’. At that point the story goes back in time to the real beginning of the story.
From there we step forward from there until we get to that scene again (classically at the Act 2 break), from where we run on to the end of the story.
Once a surprising, even exciting, technique, now it’s a cliche.
However, you still see it on screen all the time (even Breaking Bad opened like that).
The idea is that it makes your script hit the ground running, plunges you back into the story, and by taking you back to the beginning of the story, energises the first part of the script with the massive question ‘How do these innocent looking characters end up in those dire straits?’
A good flash forward still works well
1. It is a terribly, terribly common technique these days. And terribly common is not what you want when you are trying to impress.
2. If it’s done right, then, when you get to the scene/sequence the second time through, you really ought to have something different to say about the scene.
The second time round the audience should see the same scene on screen, but understand it completely differently. Otherwise it’s a simple repeat beat, and they are boring.
(See The Hangover for a good example of how they make it work, and what new information surfaces at that point to propel the story on.)
3. It makes me think that you have trouble writing beginnings!
A beginning should be strong, intriguing, powerful, and ask story questions that makes you want to know more.
A flash forward will do this – but there is so much more you can do.
Instead of using this trick, I suggest you look at the characters at the time of the beginning of the story and see what you find about them – at that time – that is currently strong, intriguing, and powerful – and start your story there.