Running your own business is difficult, most people who try fail.If you are skilled at what you do and run a diligent business you will find loyal customers. Some builder I have worked for over 15 years and always get me to do their work, dont even give them a price, just work on charge and send them the bill. Some will try other contractors and come back when they realize cheaper isnt always better. The link is a very basic outline of a formula, to do it professionally you need much, much more, which requires many years of experience, then you need the business skills on top of that as you must realize. As you say when you work for someone you need to keep within what they want and what you can deliver, thats a challenging skill, if you want to step out of that structure you do in your own time in the realization its likely to have no monetary value. A few few photographers get full artistic freedom, that is not the norm. I was talking to a long time professional photographer about how so many armatures are trying to get into the business, he said, lets see them organise a $10 000+ outdoor photo shoot with models, make up, designers, time restraints, council fees, insurances, the weather etc. and see how good they are.