I am reading Finale by Becca Fitzpatrick. It’s the last book in the Hush, Hush series. There are four book in the series. The first book introduces the protagonist and sets up the rules in her world. Angels are real and not all angels are a”angels”.
The second book focuses on Nora’s relationship with Patch, her boyfriend/fallen angel. Each book creates more obstacles between Nora and Patch finding the chance to share their love for each other. The fourth book takes of where the cliff hanger left off with Nora now being the leader of the Nephelium, placing her at odds between fallen angels and her true love.
When you write and if you decide to create a series and now-a-days it seems like a good idea think about what each story will focus on. Select a few relationships and go from there and of course read some on the best-selling series that are successful. My Books You’ll Love section will give you plenty to choose from.