There are so many ways to do a spirituality biz.
Start by doing a few months of research on what already exists and what other people have done. Search the web, you'll find tons of stuff. And think outside the box of being a guru.
Also think about the biggest obstacles you faced in your spiritual journey and what kind of problems people commonly face in spirituality. You can basically start a biz around any single common problem.
In general, in order to enter an industry you must first become an avid consumer of it. As you consume and explore the industry you will see what works, what doesn't, what's missing, and what niches are available. You need a lot of experience consuming the industry you work in to find opportunities and to learn from what has already been done.
I broke my way into self-help by consuming a ton of self-help and seeing gaps and opportunities. No one was doing self-help in the way I wanted it done, so I started my own channel.