To quote from Patricia Highsmith, author of The Talented Mr. Ripley, and Two Men on a Train (Alfred Hitchcock turned this into a film) and 31 other books:
About the main character:
Does the reader care about him? Above all, one should find out the general impression the book makes in its present form. Is the hero too priggish, tough, humorless, selfish? Is he admirable, if you want him to be admirable? DOES THE READER CARE ABOUT HIM? ....She further writes: Be honest about the last question. It is not about liking the hero. It is caring whether he goes free, or caring that if he is caught rightly in the end and it is being interested in him, pro or con.
According to Evan Marshall from his book, The Marshall Plan for Novel Writing:
It's vital that your reader like your lead [character]...
He breaks down four qualities that are essential: Courage,virtue, likability and competence.
I immediately asked what those qualities meant. In examining main characters from my stories, they possessed these qualities, but I never knew that consciously. Marshall gave excellent explanations of the qualities, but I didn't feel those on a significant enough emotional level. I didn't want to begin describing a character in a cavalier way such as "William was a courageous man." I felt virtue had to penetrate the reader at the deepest level, like muscle memory. I wanted these qualities to become part of my writing. Whenever I get something intellectually, but not kinesthetically, I want to drill it into the furthermost reaches of my experience.
Here's what I found that helped me really "get it":
Courage in a character means he or she can face fear, pain, a lack of certainty about a situation or danger. Sometimes it means handling intimidation without buckling. I remember feeling that way about Harrison Ford's character in "Raiders of the Lost Ark" the first time I saw it on the big screen. The guy was relentless. I don't recall that experience of him in the sequels. I imagine that the director used the success of the first film as a stepping stone, turned it into a sort of a contrived comedy. I wanted the Indiana Jones who beat the odds and took every risk without stopping even in spite of enormous physical pain.
Courage is acting in spite of fear. "Physical courage" is courage in the face of physical pain, hardship, or the closest encounter with death; while "moral courage" is the ability to act rightly in the face of popular opposition, shame, scandal, or discouragement.
Humans are not wired for courage. When faced with danger, humans experience an autonomic fight or flight response. Whoever designed the human brain put five sections in there to trigger the fear response. Fear triggers all our responses including the fight response. We can't help it. Many of us handle fear by becoming angry.
This scenario does not endear a lead character to us. What does then?
Once again, courage means a character can act in spite of fear. Conviction about ones beliefs allows us to move forward to reach the story goal with terror staring us in the eyes.
We can experience two things at once including having the electric shock of fear in our body and act at the same time in spite of our hard-wiring. Here's an example.Years ago, I took a course in public speaking. Public speaking is the most powerful phobia we have. My instructor had me give a speech while I packed a suitcase. The exercise demonstrated that I could feel waves of fear standing in front of people and still perform my job.
Our lead character is believable to the reader or an audience if he has strength of conviction. If one has a true commitment to their beliefs, he or she will die for them. A coward won't. A coward will give up his or her beliefs. He or she will be alive, but won't have anything in which to believe. That's not inspiring.
A believable scenario will have your character committed to something bigger than his/herself. Narrate that.
Virtue in a character means he or she has a value system or code of honor consistent with morality. Of course, that's partly a subjective quality, but regarded as beneficial to the whole of society, his family, lover and so forth. The character can sacrifice for the ultimate good. The character has this if he knows right from wrong and behaves consistently with that knowledge. The antonym of virtue is vice.
In The Missing, Tommy Lee Jones' character, Samuel, pays the ultimate price to save his family. By grabbing, gripping and dragging the evilest antagonist I can remember, Eric Schweig's Pesh-Chidin / El Brujo, Jones jumps off a high rocky cliff killing both of them. Why? Because he couldn't defeat El Brujo any other way and he had to save his family and the kidnapped girls they rescued along with his grand daughter.
As in courage, your character will need to have a belief system to which he or she is completely committed. The audience will have an affinity with those beliefs. In the classic movie, A Man for All Seasons, Sir Thomas More demonstrated a willingness to die rather than compromise his values.
Thomas More's courage was based in virtue. He died a martyr's death facing and accepting annihilation rather than giving into Henry VIII's whims and threats.
In your story your lead will need to demonstrate virtue in as significant a way as possible given your genre.
A character is likable when you find him or her pleasant and, or attractive, appealing and agreeable. I recognize likable people, but I find it difficult to define them. I think of someone who smiles authentically, laughs a lot and enjoys others company. Tommy Lee Jones has a charisma that people like. He's a minimalist as an actor, but his mannerisms are unquestionably likable.
Combine courage, virtue and likability and you have a person someone can care about. Make that person able to recognize when something extraordinary is wanted and needed and knows how to provide it and you have a character we can admire and in whom we can believe.
A virtuous man with no sense of humor doesn't make for a likable character. I think of arrogance. An unsympathetic woman like Angelina Jolie's character, Lisa Rowe, in Girl Interrupted, (for which Jolie won an Academy Award) had no empathy for anyone. She was an antisocial [sociopath] and ultimately the antagonist of everyone in Claymoore Hospital. The other actors, including Winona Ryder, Brittany Murphy, Whoopi Goldberg and Vanessa Redgrave, all had redeeming traits.
Ryder's Susanna Kaysen demonstrated courage, the ability to distinguish right from wrong, empathy and competence in getting herself released from the psychiatric hospital. People liked her because she's not only attractive, but because of her voice, ability to laugh and bond with people. (By the way, the character she play - the real Susanna Kaysen - wrote the book.)
This essay cannot encompass everything that makes a character likable. Sometimes we can like an anti-hero, but I wouldn't want to take that on. Patricia Highsmith made an art of that. She created one likable character after another, especially out of Mr. Ripley. How? I really don't know, but it worked.
You will know if your reader will like and care about your lead during the initial crisis of your story. If the reader wants to put the book down immediately, you did something very wrong.
Remember, your lead will need the courage to overcome crisis; fail and get back up; beat overwhelming odds with dignity and moral courage and make you like him or her.