I've talked before about setting the right mood, but this concept goes beyond that. Setting a mood is hard, but evoking an emotion is even harder. It goes beyond the reader just understanding what the characters are going through. Instead, if you can get an truly emotional response from your readers, it shows you've connected with them. This has now become more than a simple story - it has become something they are now invested in. Whereas before a reader may have wondered how the plot would resolve itself, emotionally connected readers now want to know that the characters are going to come through everything. They laugh when the main character makes a joke, and they cheer when that same character overcomes adversity to win the day.
Think about the stories you loved the most and kept going back to re-read - they all got an intense emotional reaction from you, from Marley and Me to The Shack to Black Beauty. These tales got readers so involved in the characters that their sadness became the readers'. Readers saw people they cared about going through tribulations and kept turning pages in the desperate hope that their favorite character would be able to overcome the tragic events in their life.
As I wrote Wrongful Death, I knew I needed to create a similar dynamic. Christian Gettis, the main character, sees it as his mission to haunt and torment Barbara Millings, the woman he has been told is responsible for his death. However, the opening scene where Christian wrecks his car and is killed is intentionally vague. Why, this could've been an accident, and any one of us could've panicked in the same way Barbara did. So what could I do that would make Christian seem like less of a bastard for what he does to her and more like a spirit whose anger is justified?
I had to show the ripple effects his death caused on those he cared about most. I wrote about the downward spiral his girlfriend was going through, as well as the indignation with which his friends would react to insults towards Christian by people who didn't know him. However, it's the interaction with his family that was critical.
Christian has the type of relationship any teenager seeking his own independence has with his father, which is to say that it's complicated. At the beginning of the book, he refuses to call his father dad, instead addressing him by his first name, Walt, probably because this would annoy any father if his teenage son did that. Christian felt his dad was an uncaring overlord, sitting on high and ruling the family with a stoic demeanor that glossed over anything deeper. Even after death, Christian refused to budge an inch on the man he felt had the emotional range of Mr. Spock.
However, he eventually got to see behind the curtain and witness his father's grief over losing a son. If you have trouble imagining your own parents breaking down to the point where they'll sleep with an old photo of their son like it was a teddy bear, then think about how you'd react to the death of a child. Christian witnesses this, and trying to get the reader to understand this level of sadness has been one of the hardest yet most critical parts of the book. If I can get the reader to feel for Christian and his father - it's no small point that after witnessing this, the main character starts referring to Walt as dad again - then it'll build up a well of sympathy the main character will need when he does some truly vile things to the woman he believes to be responsible for his death.
Most of my work tries to play on that element of connection, and some of it is more successful than others. It's hard. You can't just say, "This is where you should shed a tear." If you're too heavy-handed, you'll turn the reader off and he or she won't connect in the way needed to keep turning pages. And if you lay off too much, the reader won't appreciate it when the main character overcomes the obstacles and triumphs over his or her adversity. But when you can make the reader feel the emotion along with your characters, then you've created something special, and hopefully something that person will come back for again and again.