on Fiction University:

When my editor at Kensington Books asked if I’d like to write a novella for a romance anthology, I leapt at the chance to try something new.
Then I panicked.
I’d written six novels and a handful of short stories before, and what in retrospect could be considered novella-length fanfiction, but never a complete novella introducing original characters and putting them through the paces of a full, three-act story arc in 1/4 to 1/3 of the length of a regular novel.
Any writer can tell you that “panic” is just another word for “research.” To procrastinate, er, learn, I scooped up novellas left and right. From historical and contemporary romance to holiday and location-themed collections, I focused on standalone novellas, but it wasn’t until writing my own novella (“Mind Games,” the third and final story in the Summer in the City romance anthology) that the lesson stuck: Characters in novellas are no less complex than those in novels, nor is it any easier for the romantic leads to earn their Happily Ever After. All the same beats occur in a novella as they do in a novel—they just occur within 20,000 words instead of 55,000+.
Here are five ways to make sure the characters and story beats in your novella are as memorable and engaging as possible, while keeping your word count lower than a novel’s.