How to Use Persona
Persona is the heart of character development. So, in order to develop a persona, you must think about your characters. Who are they? Where do they come from? What do they want? What do they think about? What do they love? What do they fear? Your personae will be built around these details.
An actor preparing to play a role may be instructed to write a “silent script” about the character he will portray. This is a fictional story he writes for himself about his character’s history and motivation. In your own writing, for your characters to be real, they must also have histories. They must have reasons for doing the things they do. These are the hidden foundations of their personas, that make them believable. So, as you write them, think about their histories. Write those histories down. Then you must make the effort to give each character specific unique ways of behaving and speaking that reveal their distinct personas.