... in case you were wondering. I have published stories, but that doesn't mean I know what I'm doing.* In fact, each time I start one, I have less of an idea of what is supposed to happen. There's supposed to be an arc, I gather. You're supposed to create interesting characters that the reader--quickly!--comes to care about. The story should create an overall experience of surprised satisfaction--the reader did not see that ending coming, but at the same time realizes no other ending could be possible. Some kind of turning point should arise; some permanent (even if seemingly minor) change should occur.
Or not. You can throw together a bunch of seemingly unrelated fragments (although I'd appreciate it if you wouldn't number them). You can take on a persona and rant in character. You can obsessively attend to the details of the story's setting, and then never actually tell the story. You can write the story all in dialog, or write no dialog at all.
I find this lack of parameters disturbing. And I do not understand how some people can just produce one story after another, one collection after another, all of them quite good. Do they have some kind of basic formula in their heads, which they alter and bend and break, but still at least start with? Because I feel like I'm starting from scratch every time. I don't trust conventional arcs, but I still want something to hang my hat on. Lots of people will say that hat-hook is character, but I don't really trust that, either. To me, character--outside of a specific setting, situation, tone, voice, structure, and purpose--doesn't mean much. I need all of it to come together, and that never happens in the same way twice. I'm not sure how to make it happen, other than to be patient and make lots of mistakes, and accept that some stories, as originally conceived, will never succeed.
Which brings me to the only other technique that sometimes helps me: smushing together two failed stories or story fragments. On their own, these stories don't suffice, but together they generate enough friction to start a fire.
*I also don't know how to write novels, although I've written two (well, 1.75). But having more room to maneuver within the novel somehow makes this not-knowing less dire. All the fumbling around eventually becomes the novel itself. Which is why the novel imitates life, right? Fumbling = living. But a story can't fumble. Or can it?