The most important character in your screenplay is your protagonist: your hero. But when creating your hero, audience connection is key. Your hero needs to be an interesting somebody who wants something badly and is having trouble getting it, AND also a somebody that the audience cares about – somebody they hope and fear for. But when creating a complex character, simply knowing what's beneath the tip of the iceberg is not enough.
In order for your audience to be emotionally invested with your hero, you must also (1.) know the hero’s goals and dreams, (2.) be aware of what the hero will learn, and (3.) make sure the hero is someone the audience will empathize with.
Know the Dream/Goal
This is more than just knowing the hero’s main objective – that is, the pursuit of what your protagonist is trying to accomplish that gives shape to plotting the main story of the film. You must know every dream, want, and desire. Take, for example, an action film in which your hero is on a life and death pursuit to rescue his abducted daughter, the main objective is obvious, but what about all the other goals: does he regret the past and promise to be a better father, does he secretly wish for acceptance, or is it something more tangible, like the desire to take his daughter to a Yankee game for the first time? The more you understand what your hero wants – both internal and external – the easier it will be for your audience to champion his causes.
Every action has a reaction, and nothing is as easy as it seems. The reality is that situations are complicated, especially what's beneath the surface, and even though it is obvious that your hero must be aware of the main objective, it is usually a mistake if your hero is aware of the full dimensions of the theme at the beginning of the story. It’s okay for your audience to see the big picture (or not); sometimes you want your audience to discover along with your hero. But regardless of the creative decisions you make as to what the audience knows and when, it is important that your hero learns along the way. The theme – and its implications – should be revealed on your hero’s journey.
Sympathy vs. Empathy
Creating a hero that we feel sympathetic toward is a HUGE help. It’s almost impossible not to care if we feel sorry for someone else’s misfortune, not to mention that sympathy often equates to likability – and a likeable hero is easy to hope and pray for. However, sympathy is not the essential ingredient. Empathy is the key. Not every hero is likeable or should be; there are many heroes (or antiheroes) that we dislike, but we stay with them because we’re able to understand why they do as they do. In the film Monster (2003), for example, Aileen Wuornos (Charlize Theron) is a serial killer. Clearly, we should not like what she does nor condone her cold-blooded killings, but because we can empathize with the realities of her cruel childhood plagued by profound abuse, we hope she will be able to survive none the less.