I think this is where you start. Something that interests you, something you have knowledge around, something you will actually find useful yourself in your lif

I think this is where you start. Something that interests you, something you have knowledge around, something you will actually find useful yourself in your life or career. Second, and more challenging, is getting traffic to it. The best product with not traffic is worthless. Over the longterm, content and SEO are one channel. This takes time and is hard work. But it can be outsourced some. Be involved in communities and forums around it. Buy advertising. More than anything, build and product content. If something is working, double down on it.