When I started http://fairpixels.pro (UX/UI Design for B2B Saas Companies) I grew it pretty quickly to a very profitable one-person business. (Not 1 person anymore)
The origin story is somewhat organic.
- Started as a logo design company
- then kept getting requests to help with UI/UX Design so I did
- then realised the most fun projects to work on were B2B SaaS companies
- today we're still growing and can happily count Fortune 500 companies, an Elon Musk company alongside awesome startups to our client list.
//Advice: Start with something small. Anything. Don't worry too much about how to grow. Then.. Just keep your eyes & ears open. Your customers will point you in the right direction towards bigger pinpoints & thus better growth opportunities. You don't always need a ton of traffic. Just start with something small and go from there.