I might have the funniest answer here....
The instant I started photography, I was a PRO. I can and did support myslelf for several years by taking pictures. I find it ironic now, 28 years later, trying to answer this question and finding that I have worked my way DOWN the progression fro PRO to a newbie.
How is that possible you might ask?
As a PROFESSIONAL, I did not have the option to fail. There were hard and fast rules that were followed, no matter what. There was little room for experimentation.
Now, I have the freedom to experiment and take chances, and apply my own artistic expression to what I do.
Recently, I attended a "country team roping" event out of town quite a ways. As an embedded habit, I immediatly set up to get the "money shot", which bragging a little, I got pretty quickly. It then came upon me, that I had the freedom to experiment a little. I stayed for hours (and actually followed the event to a different city on the next weekend) taking different kinds of pictures. I played with motion blur, slow shutter speeds, and several other ideas that turned out really well. Had that been an assignment earlier in my life, I would have never taken any of the chances I did.
Now, even though It is not my full time carreer, I truly enjoy this hobby with a great deal of knowledge and a wealth of experiences behind me.
happy shooting