I would think most of us started out part time ADC and built our businesses from the ground. Particularly the old generation men like Paul W., myself, Mike Page, Ron Jones, Rob Erickson, Phil Nichols, Ron Frye to name a few and so many others who are of retirement age or getting ready for it.
There wasn't much info or training back in my early years in the late 60's early 70's. I had a day job that financed much of my early ADC equipment purchases, aided my learning curve time and provided finances to build my lure business. It went that way for many years until I had built a versatile skill set of services and acquired enough equipment to work with to handle all my service call needs and allowed me to fly solo doing fulltime ADC, Pest Control, Fur trapping and Lure formulation.
That is an act I still do currently with employees and part time help of course. You fellas think you are busy.

Things are much different now. Trade skills can be learned or bought thru training at a more aggressive manner then ever before. You do still need to pay your dues in learning and applying your skills over time to establish yourself and your abilities. There is no fast track for that.
Everyone wants that quick fix now a days, however it still requires considerable training or hands on experience or working with someone who is willing to mentor you along the way. You need to start with services that you can master one area at a time and continue to add on to your skill set to where you are well versed enough to get going.
The service end is just one part of a small business venture. The other components like developing your language skills to speak to customers, sell jobs, diagnose problems, get your needed paper work /accounting skills in order, establish business skills in billing, collection practices, terms and people skills all are a part of the total package.
Resolving the nuisance problem is only the tip of the ice burg and usually the easy part. Its the other areas that make or break you. Every one has to start somewhere if they have a sincere interest in a business venture. There are some folks on here that have been there and done that. Having a patient and supportive wife or family is a key component in allowing you to grow your business.
If you don't have that, or someone that can help to finance your venture while allowing you time to grow can be a make or break situation for many aspiring to build any kind of initial sole proprietor business.
Some have started on their own for a while and found that running a business was just not what they wanted to do or could do. So the options were working for another company as an employee or buying into a franchise or going another direction all together. Some have done all of these things and they certainly can give you their take and views from their perspective if they choose to chime in on this topic.
There has been a lot of info already discussed on this topic over the years in the archives. Most of the questions that you have will most likely be found with some research and reading under previous similar topic discussions.
Best of luck to you.