This is a very old thread, but I'll mention significant personal prophoto-factoids:
When I decided to "go pro" it was an easy step. Thanks to Conrad Forbes, a Minor White direct student, I was doing good large format art photography in Northern California. I showed portfolio to an architect, did good work for him (B&W), then got as much architectural photography as I could justify from his company and others: architects pay poorly after taking their time paying.
So I moved to San Francisco, worked in a pro-photo warehouse kind of place, then ran an E4 and audio visual production company...got fired for attitude...
I asked someone I admired how to re-start shooting solo for money. He said that was easy, all I had to do was to make a list of 100 possible clients, go down that list showing portfolio. In the first week, by the 6th interview (as I recall) I was getting work, mostly 4X5 E4, food and tabletop. $400 minimum day rate, nothing by the hour. I never lacked work for more than a couple of days for the next ten years but decided to pull the plug and change careers when I realized I didn't want to socialize with clients.
I quit to join Merrill Lynch, quit that after a couple of years because, again, I didn't want to socialize with clients.. became a self-employed headhunter, suddenly did very well with that after first several months...a wonderfully successful business for a decade or so without having to socialize with anybody. My clients were mostly banks...9/11 killed that, probably a blessing