I heard Greg Isenberg say something on a recent podcast that I hear several times a week. Start with the niche. He’s right. I’ve been on Greg’s podcast. I learn a lot from him. The advice is correct. Start narrow. Dominate a small market. Expand from there. The problem is nobody talks about how. “Find your niche” is exploit advice. It assumes you’ve already explored. It assumes the niche is sitting there, obvious, waiting for you to pick it. Most founders, creators and marketplace builders…