Insist upon yourself. Be original. - Ralph Waldo Emerson
When it comes to screenwriting, you don’t necessarily need an original idea to be successful. How many times have we seen Romeo and Juliet? Hundreds? Thousands? It’s a simple story really. Boy meets girl. Girl meets boy. They come from opposite sides of the tracks. Families hate each other. But despite everything, they fall in love. Now Shakespeare takes them to a tragic end. But there’s no rule that you have to. And if you’re writing a romantic comedy, you sure as hell better end with something happy. The audience demands it. We know exactly how a rom-com is going to end before we sit down. The journey to get us there is the fun part.
It’s wonderful if you do have an original idea, a plot we’ve never seen before - hold onto it like a Wonka’s golden ticket - but if you want to be a working screenwriter, don’t feel as if you must reinvent the wheel. It’s okay to rip-off a plot we’ve seen before, but the way you disguise it from it’s forefather is key. Avatar was Dances with Wolves in Space, and Dances with Wolves was Pocahontas on the Western Frontier... and so it goes.
The trick is to change the world while incorporating remarkable and unforgettable characters: Romeo and Juliet as divorced ex-starship trooper marines working for competing deep sea oil companies on a new mineral rich planet, living within an underwater city at the bottom of the deepest ocean in the known universe. Same story... different everything else. Your originality comes in the everything else. To say James Cameron is not original is laughable, but to say Avatar was an original story is arguable.
When it comes to three act structure, sequences, and major plot points - all key ingredients to a successful script - again, originality is not a primary concern. If fact, it is quite the opposite. Almost every drama is about two hours: 30 pages for Act I, the next 60 for Act II, and the last 30 for Act III. Most comedies are about 90 minutes: 24 pages for Act I, the next 48 for Act II, and the final 24 for Act III. There is nothing original about that. Can you image every novel locking it’s protagonist into a predicament between pages 24 and 30? The novelist has freedom to go anywhere, do anything, at anytime. The screenwriter, conversely, has an expected structure with sequences and plot points: inciting incident, lock-in, mid-point, main culmination, third act twist... and so on. There is not much originality when it comes to the rough carpentry of building a screenplay.
But despite all this, originality within the screenwriter’s voice is paramount. If you’ve done your homework, you know your characters so deeply that they’ll begin to write themselves. You just put them in the right situations so that they can interact, but the way you describe the action within each scene becomes your personal canvas. And you must paint - being clear, concise, and creative - with an original stroke. Word choice, rhythm, the stylized use of fragments, sounds, and sentence flow - that’s all part of it.
Two or more writers could be given the exact same non-dialogue scene assignment with detailed direction as to what must occur, but the voice of each writer should ring different. Same story; different execution. Remember, you’re no robot, so don’t write like one. It’s your voice. Your stamp. Your brand. Make it original.