From what I have seen in my area, there seems to be three successful business models: Large volume but limited service provided, small volume, but large amount of services provided, and medium volume and high service level.
Ex: Large volume/limited service would be a facility that has limited need for staff by feeding round bales (or pasture), not offering inside board, and not offering a lot of on-demand extras. May or may not have a lesson/training program. There are a few places like this around here that have 75+ horses on sight because of their limited offering of service, don’t require full time staff. Low rates ensure demand despite being quite busy.
Small volume but large services would be a smaller facility (under 30 horses) but that offer training/lessons, and some indoor board. The small amount of indoor board means that one person can handle chores if needed, but the additional revenue streams of training/lessons allows for additional staff (grooms/instructors that can also help with horse care). Good for an owner/operator that can provide training/lessons.
Medium volume/high service is 30-40 horses, typically with a show coach/program, grooms, training programs and such. High price/service level allows for high staff per horse ratio. Of course you will be expected to maintain a consistent high level of service.
Businesses that do not seem to do well are the ones that rely on one staff person with no back up: if they are sick, injured or lazy, the quality of care can suffer quickly. Having on-site (live in) help can make them more reliable, but if they quit/are fired, evicting them can be complicated.
If you are female, look for a group/club for women entrepreneurs. They can open up doors to grants, resources and helpful support/advice. It doesn’t have to be equine specific to be helpful. Basic bookkeeping and business courses can help with management even if general (not equine specific), and can likely be done online, but taking an actual course may help you more (as you can better address specific concerns).