There is a discipline needed to be a good (or great) photographer. Practice, practice, practice. Of course it also helps to have God given talent and shooting the subjects that you enjoy.
I, myself, don't really care to do portrait photography. Portraits feel too controlled and posed for me. I love candid portrait photography but I most enjoy nature and animals. When thinking about making fine art photography a business, you look at every opportunity as a potential photo shoot. When planning your day, make sure to pack your camera (either in a proper bag, or in your purse (which is what I do). You just never know when you will come upon something that literally speaks to your heart, and has the potential to speak to your wallet :-)
My mom and I were "junk" shopping on Sunday when we drove past this grove of evergreen trees. I was intrigued. Not only because they were plenty tall and beautiful, but because they were grown in dozens of straight lines. The results were this impressive maze of perfectly ordered tress in the ordinary chaos of nature. I immediately pulled over my car and captured the following image:

I love how it turned out. This has become one of my favorite shots. You just never know what you will come across. It pays to be prepared.
Cheers
~Lora