Why are some actors not very good? Talent, of course, is part of any discussion about any art. But just setting aside talent for a second, when an actor isn’t truly in a scene I think it’s often because they don’t understand the character. Or they understand the character only in a surface way and so their lines and expressions and body language all seem untrue. I think this is what happens to writers. They force themselves along and a scene just gets less and less true. The reader feels it when reading the manuscript. The writer isn’ t there in the scene and the scene feels false.
How do you get there inside the character? I think writers find different ways. Some outline. Some journal. Some write and rewrite and rewrite and rewrite and so on. Thankfully, we have many chances. But one thing to consider is you have to try to see the scene unfold in a moment-to-moment way through the eyes of your narrator. When you’re actually writing the scene, you have to try to be there by living the scene. If you’re there in the scene, you’ll make the right decisions and the scene will be true. Of course, you should test and retest this in revision but being there in the scene will allow the fiction to move forward in an organic way so that the plot grows out of the situation and characters.
It’s a constant struggle and it isn’t easy but one thing I do always try to do is see the scene unfold through the character.