Short story, novella/novelette, or novel. Settling on one or the other can be a difficult task for the inexperienced. Each format has its own peculiarities, and the unwary sometimes get halfway through what they think is a novel before they realize the story’s legs are too short to finish the job.
Starting off writing short stories is generally a good approach, regardless of any novel-writing ambitions. Whereas a novel is likely to have a complex narrative just by virtue of sheer length, the contents of a short story are far easier to keep straight, making one’s first experiences self-editing far less frustrating. Short stories are also great exercises for writing conservatively. Give someone only 3,000 words to voice an idea and it’s unlikely there’s going to be much of the bloat associated with poorly-written novels. It’s far better to learn to write tightly-woven fiction before taking on 80k and up, and it’ll give a writer a far better idea as to how much space an idea actually requires before moving on it.
Novellas are the formats for those stories that do have legs, although not enough to cover hundreds of pages. For aspiring novelists, novellas can be the next step up the ladder toward novel length, offering enough space to test one’s abilities to weave more intricate narratives and a deeper level of characterization. Novellas are also a great fit for authors with a lean style and a preference for the intimacy of a small cast of characters. However, any who settle on them as a preferred format should realize there are very few markets receptive to them compared to novels.
Novels are reserved for the epic tales. Often containing large casts and jigsaw plots, hundreds of pages are required to adequately develop everything in a satisfactory manner. While easily the most marketable–and by extension, potentially profitable–of the three formats, a writer has to earn the page length. Like any piece of fiction, a novel risks losing its reader at any point. Due to length, plot holes, character inconsistencies, and (especially) meandering are all more potent dangers to a novel than a short story or novella. This is particularly true of new writers who start out in this medium, as they usually lack the discipline and polish learned from the shorter forms.
Regardless of what format an author favors, it’s always best to smart small and build the necessary skill to move up. Just as an engineering student shouldn’t play with a nuclear reactor, an amateur writer hellbent on a 200k epic is equally likely to leave one hell of a mess in his wake.