I was recently watching Best Wishes, Warmest Regards: A Schitts Creek Farewell on Netflix, and I strongly recommend it to any fans out there, but they made a lot of really great points in terms of character development.
No one knows better than authors and writers how important a good backstory is. And for a show like Schitts Creek, from the first episode until the last, you are still learning new things about the characters and I think that is what made it so addicting and real. In the documentary they discuss how they worked on the backstory for weeks before they started filming because they didn’t want to move on until they knew exactly who these characters really were.
As writers and authors I encourage you to do that with your work. List out your characters attributes and their individual backstories to fully understand who they are, perhaps before you even start writing. As readers we want to consume an emotional investment on the characters, and in order to do that we need more than x, y, and z! We need to fill in the cracks!
Think about it as if you were casting your own show for your book. How would the character portray themselves in a room, what would they wear, and how would they talk? All of these things play such an important role in a reader’s mind.
And as always have fun in creating them! They are a piece of your own imagination afterall!