We all know that our main character's need to change over the course of a story. Otherwise, what was the point of it all? But a lovely writer in the Go Teen Writers Facebook group asked about how to show that the character has developed without it feeling like a clunky aside.
While there's no one way to do this, I have a progressive checklist you might find helpful:
Let them fail the first time
Once you've figured out how your character needs to grow, show them failing at it early on. Say you have a character with oppressive parents and she wants to do something to strike out on her own. In the first chapters of the book, I would have her attempt this and fail. Maybe she goes into the conversation planning to be mature, but gets angrier and angrier until she knocks over her mom's shelf of cookbooks in a fit of frustration.
Allude to times of practice
Throughout the book, you'll want to build in times for your character to practice this new trait or skill they want/need to learn. For a trait like bravery or independence like we were just talking about, you might put your character in a situation where she's learning to speak her mind in a clear, productive way. Like student government or debate class. Something that doesn't directly relate to the conflict with her parents, but that will help prepare her for a future battle with them.
For a skill, the example that comes to mind immediately is Harry Potter. We don't have to be with him when he practices every single spell or charm because we know he has classes everyday. The reader automatically gets that Harry and his friends are growing as wizards.
Have another character point out the changes taking place
If handled wrong, this can be completely cheesy, but it doesn't have to be. Again, in one of the Harry Potter books, he's confused why girls are suddenly paying attention to him, and Hermione points out that he's grown about 5 inches over the summer. It's a much more natural thing for Hermione to say than it is for Harry to think.
Give them another chance to win their battle
They failed the first time, and now you need to present them with another chance. So for our character who needs freedom from her parents, winning might look like a conversation in which she communicates effectively with her parents and gets what she wants ... without flying into a rage.
Or in the movie The King's Speech, we open with Bertie failing miserably at a speech, and he's given a chance to redeem himself at the end.
Can you think of other examples where this is done well in a book or movie? (Try not to spoil anything!) Have you build in tests for your characters?