Recently, I critiqued a novel that was clearly meant to be the first in a series. “We need an ending, a resolution. Right now, it feels like someone snatched the manuscript and ran away before you were done.”
The problem with a series is that you need overarching goals for the whole thing, be it a three book trilogy and an ongoing series with 20+ titles. You also need a plot that is somehow resolved in each individual volume. To find out how to do this, read Rae Carson’s The Girl of Fire and Thorns and then the second novel, The Crown of Embers.
In the first book, a naive young princess finds herself married off to a man who doesn’t love her and in a land that is falling into war. She is lost, alone and completely out of her element while also married to a man who sees her only as a political benefit. Carson ties up the plot in the first book by having Elisa, our princess, find a place, develop skills and friendships and even become friends with her husband. Note: the problems of the kingdom are not solved so neither are biggest Elisa’s problems. The series goes on.
In the second book, we find a young queen who wonders which of the people around her is a true friend. She wants love and belonging (still) and a true purpose (what should she do to solve the problems swirling around her). By the end of the book, she knows who loves her for who she is vs what purpose she can serve, she has succeeded in a quest, and she has started to learn to harness her greatest power.
But things are still not entirely rapped up. The man she loves is snatched away, war is eminent and she still doesn’t know everything there is to know about power.
Do you see what Carson has done? Many smaller problems are wrapped up but larger problems remain. There is a resolution but still a thread drawing the reader forward.
Read, study and learn.