Write self-help listicles. There are a million people on Medium writing that dreck and for some unaccountable reason they all get a gazillion claps.
Or you could write about how to be a successful writer. That's a gold mine as you can see already. All you have to do is write the same nonsense over and over. Just be sure to change the words.
I'd suggest disaster porn but that niche is sewn up by U. H. and J. W. If you don't know who they are you must be REALLY new to Medium.