Well I thought long and hard about this one - obviously. What would be the one piece of advice on scriptwriting. And by that I am limiting this to the craft of writing rather than the career of being a writer.
It has to be an idea out of the book Screenwriting: The Sequence Approach.
There are lots of ideas even in this one book. And there are many books out there. But there is a single idea that helps me. It is not about structure, or techniques. It is not about dialogue. It is not about layout. It is this...
For each character know what they want. And know what they need.
They may think they want to get through the working day. But we all know they need to change their home life priorities.
They may think they want to survive the shoot out. But we all know they need to discover their partner is a rat.
So many examples. And it is so simple. But without it your drama, whatever the structure, is flat. So that is my number one piece of advice. What is yours?
Photo of Jason Arnopp as taken by me under the direction of Danny Stack.