A writer emailed me to ask about how to grow a relationship between two characters over the course of a book. This is an excellent question, and a big challenge whether you're talking about a romantic relationship or a friendship.
I had to do this with a romantic relationship in the first Skylar Hoyt book, Me, Just Different, where my main character, Skylar. met a new guy, Connor, who would eventually become her boyfriend. And a great example of growing a friendship can be found in the first Harry Potter book, Harry Potter and the Sorcerer's Stone when Harry meets his future best friend, Ron.
Here are some techniques you can use for your own characters:
Create a reason for them to spend regular time together.
In Harry Potter, Harry meets Ron at the train station, and they spend a long time in each other's company right away. Once he gets to school, he then is in the same classes, house, and bedroom as Ron. These guys are together all the time, even when they don't like.
In Me, Just Different, Skylar and Connor have a couple classes together, but they're also manipulated into carpooling twice a day.
When you've done this, you can easily
Allude to time spent together
We don't need to be with Ron and Harry every time they walk to class together to know that they do it a lot. This means that when the author says something about two weeks going by, the reader's brain makes the automatic jump to, "These characters have been together a lot during that passage of time."
Entwine Their Lives
In Me, Just Different Skylar's life becomes entwined with Connor's even when she resists. Even if she decides to avoid Connor, she can't change that their moms are friends, Connor's dating her best friend, and his brother has a crush on her sister.
Give them a Common Enemy
Even two characters who don't get along can bond quickly over a common enemy. In the first Harry Potter book, Harry and Ron bond over a mutual dislike for Draco Malfoy and a general dislike of all Slytherins.
Put them in a Stressful Situation
This is what J.K. Rowling uses to seal the friendship between the boys and Hermione. They're rather annoyed with Hermione until about halfway through the book when the three of them fight for their lives against a troll. After that, they're all friends.
Other stressful situations could be a death, a secret they must protect (in Me, Just Different Skylar and Connor are protecting Abbie's pregnancy), or even something as simple as a hard class both characters need to pass.
Getting a Glimpse into the Other Person's World
In the first season of Gilmore Girls, when Rory is at a new high school, a girl in her class, Paris, seems like the devil in a pleated skirt ... until we see her mom being horribly critical in a public setting. Suddenly Paris makes much more sense to us and to Rory. A friendship begins to grow between the girls.
In Me, Just Different Connor's heart softens for Skylar once he gets to know her family and sees how differently she's been raised than him.
And in the Harry Potter books, nothing hurts my heart more than when Ron is ashamed of how poor his family is, and it hurts Harry's heart too.
This is when two characters who thought they had absolutely nothing in common, maybe who even work against each other most of the time, find common ground. This is done so effectively in later Harry Potter books when Harry sees glimpses of his character and childhood in Voldemort and Snape.
Do you have characters in your manuscript who need to grow closer? Is there something on this list that will help, or do you have another technique you can add to our list?