For the most part - exceptions exist - I, like most I'm guessing, would like to avoid the "infodump" chapters/paragraphs.
How do you decide which "things" in a story needs explicit explanation, and which can/ought be glossed over? Any rules of thumb?
There's really no rule of thumb, except that in a short story, you really have to pare down anything that doesn't advance the plot, or is important to the impact of the story. There may be great details of world-building and characterization that just aren't important to the story, and they may have to go. Getting a balance between what's necessary, what isn't necessary, and what may not be necessary but makes the story more worth reading can be tricky. Some writers have a knack for this and others work very hard to develop the knack for it. This is why short stories are sometimes so much harder to write than novels, and why some writers stick with longer formats.
Infodumps can occur at any length, and one way to avoid them is to stick closely to the perspective of your viewpoint character, her knowledge and her actions and her priorities -- if she doesn't know the history of your world, then there's no one to infodump it on the reader, if that makes sense. You can also try to keep your exposition pared down to what the reader needs to know at that moment, to keep your plot moving or to understand what the characters are talking about.
The best rule, I think, is just to keep trying. You'll learn from each story you complete, and your next story will benefit from the experience.
Still taking writing or publishing questions here.
The thing that really makes Fall feel like Fall at our house is that on weekdays I wake up hearing the band practicing at the high school just outside our neighborhood. They start early in the morning, with a time-keeping metronome-like sound for the marching, and it's mostly the percussion that you hear. At this distance, it's white noise, and doesn't really bother me.
Also, last night a friend had a minor motorcycle accident, so that was a bit scary until we found out he was back home and okay.