I seem to do well with essays — take one point from what I’ve been doing in my day to day life that inspired me, and riff on it. Kind of a “something to make you think” slant, with a good takeaway for the reader. Like my last one was about the columbine blooming in my garden, and the Columbine school shooting, and the similarities between the two, and how I can’t see one without thinking of the other. Other people do well with recipes, or flowers from their garden, or cute things their kids do, or, well, anything really. One author I follow is writing about all of the things she is going through while writing a book (how to choose an editor, how to respond to the editor, how to deal with feedback, etc.).
I have links to all of the short forms I published at the bottom of my challenge post: https://medium.com/30-day-writing-challenges/11-11-signs-of-success-30-day-challenge-f8ba2b0803de
I self-pubbed the first few I wrote, then used those to apply to The Daily Cuppa as a writer. That’s a great publication, devoted only to short form, and the authors there read and comment on each other’s work all the time. Their followers are growing by leaps and bounds, and some of their pieces have even gotten curated, which is amazing for short form! The editor is super nice, too.