I'm currently making about $1K a month on my book/course Atomic Note-Taking which has sold in 69 countries—something I didn't anticipate! https://atomicnotetaking.com Along side this I'm build a note-taking app—flowtelic that aims to help you get into flow and have an autotelic experience. It's to put into software the goals of my note-taking book where I feel other apps are missing the mark. I have a waitlist if anyone is interested https://join.flowtelic.com