Better start building up a nice portfolio
Shall I start?
This is so old hat, plus the market is over-saturated. The chances of anyone making money any more is very slim. The heyday of getting paid for your shots is over, you're lucky to pull in anything unless you have a vast library of good quality or unique images. When I mean unique, I mean it in a commercial sense.
Plus you need decent glass/cameras for the quality otherwise it risks being unusable for a campaign.
Now the real elephant in the ring isn't stock imagery it's the lack of education of the amateurs, they don't how to manage Image Rights, Copyright or even Value. So agencies take advantage of this. A case in point an amateur could have been paid hundreds, if not thousands for an image only got $100. This was from Flickr and he only found out after when he came to brag about it.
The whole industry has become devalued where people don't appreciate the technical skill to produce images or cost of professional gear.
Digital photography isn't 'cheap' as people believe. The cost of storage can also be prohibitive when you have nearly 50,000 RAW files. Combine that with the RAW file sizes of a Canon 5D Mk II or a 7D and you will see what problems arise.
Good to know before I started
I'll stick to family pics then
Looks a pretty good camera though- but I can understand why a professional would be concerned about amateurs earning from photography.