The same as any pro ... excellent training (school and/or as an assistant to a working pro) and years of experience not only as a shooter, but in using artificial lighting, from a single bare bulb to multiple light setups with every known light conditioning attachment.
If you are going to be the owner, you will have to also know how to run a business and still make some money. You will need to make a P&L worksheet and list all your fixed and variable costs as well as figure out what your capital investments will be at start up and over the years.
DSLR's are usually replaced every 18-24 months and computers every three years. Flash tubes can last a few weeks or years, depending upon the severity of service.
