Because I just did this, here you go: Some simple ways to start a story, particularly if you don’t know what you want to write about, but you know you need to write something. (For money, for practice, for mental health, for whatever.)
Previous writing!meta caveats apply.
1. A line of dialogue. Particularly one that makes no sense, so you have to then have a second character explain it.
“You said what to the Queen?”
–Instantly you have to answer who said it, what was said, why it was scandalous, who the queen is, what she’s queen of, and who actually spoke the dialogue. Getting all that exposition in gracefully is at least 150 words right there.
2. (All of my points are going to boil down to variants of point 1, so, you know, grab a soda or something.)