Picking up the train of thought from last week, I learned a lot from writing short stories. With fewer words comes the need for sharper focus: I had to develop the skill of building a story around a single moment, a single decision, and making that complete. It's probably this process that built my liking for the "yes, but ..." ending - the conclusion that fulfills the story goal, but sets up ongoing complications.
Short stories also helped with my sense of plot. Working on the micro level (comparatively), I had to figure out the direction of the tale before I began, or I risked wandering ... and wandering into novelette or novella territory. I know there are other writers who can start a short story without an ending or outline, but I was never one of those writers, and in a few cases, I found out the hard way. Those rambly tales are best forgotten.
I also learned quite a bit about incorporating worldbuilding into fiction ... and some about faking it. Many of my short stories have allusions to cultural, physical, historical elements of the world - brief glimpses that show the workings beneath the surface. Except, in almost every case, it's an illusion: the glimpse is the only truth, and the reader knows as much as I do. Well ... almost.
But it's not all faking it. Again, space is at a premium in a short story, with less room - and reader patience - for extended descriptions. Sentences setting the scene often do double, even triple duty, contributing to the plot or understanding of character. An example I often like to give is instead of just stating that a character is tall, something like, "She was obnoxiously tall, looming a head and more over the locals," also gives some information about aforesaid locals ... and a hint of snarkiness in the narrator, perhaps.
All of these skills, this learned economy, translated back into my novels - or at least, I hope it has. Even if that's not the case, I enjoyed the ability to dip my toe into far more worlds than I might have, had each demanded a novel of its own.