While writing my upcoming novel, Natural Disaster (releasing in October!), I’ve decided one of the most challenging things was writing a sibling relationship. I grew up as an only child, despite having three older sisters. They are all quite a bit older than me, so I never really had a close relationship with any of them.

My protagonist, Jessica, has an older brother. Evan is, in many ways, her best friend. They were always close as children but also had many moments of arguing and even disl...