Seth Godin’s thing is marketing.
Ramit Sethi’s thing is personal finance.
Ryan Holiday’s thing is stoicism.
What’s the thing that replaces your morning coffee, afternoon hike, and nightly read?
What’s the thing that, once it’s gripped you, you can’t shake off?
Is your thing a combination of things that make it impossible for you to fit into a single niche? All the better. You could be the world’s only host of a podcast about one-handed juggling, author of a weekly e-mail newsletter about mushroom tea, and critic of 19th century Italian literature.
If you can’t think of anything to do, there’s always the option of moonlighting as yourself.