When you're stuck for what a character in your novel or screenplay would do next, there's a simple question that can help you decide.
As novelist Lili Wright ("Dancing With the Tiger") points out in an interview in The National Book Review, how you phrase the question is important. She credits it to screenwriting guru Robert McKee:
"Don't think, What would I do?
Or, what would the character do?
But: If I were him or her, what would I do?"
It's when you put yourself into the character's shoes and interpret the situation from his or her perspective that you're most likely to hit upon the most logical and true next action.
For instance, if you (the writer) came across somebody fell into some bushes and obviously is in need of help, probably you'd go to their aid. But what about your character's reaction to such a situation?
Let's assume your character has a good reason to want to stay out of the spotlight.
If you ask yourself simply, "What would the character do?" you might conclude that she hurries on, hoping someone else will come along and help the injured person.
However, if you imagine yourself to be the character and create that image of the injured person in your imagination, you might find that simply leaving the injured person and doing nothing else makes you feel too guilty.
As this character, what else could you do? For instance, maybe you'd hurry on but, keeping your head down, say to the next person you encounter, "I think there's somebody over there who's injured," hoping that person would choose to look and help.
Vividly imagining any situation from the perspective of your character allows you to tune in to their emotion as well as the logic of how they'd react, and that will make it more authentic.