Who hasn't heard of Graham McNeill? He is a writer and former game designer for Games Workshop. He now writes for the Black Library. Anyone who has read any Warhammer stuff will probably recognize him.
He keeps a great blog and I enjoy reading his stuff. He makes me believe that a "normal" bloke can make it as a writer and it sounds like a life I would love to lead.
I have even considered pestering him with the typical questions such as "how he made it" and all that jazz.
I suspect, though, that the answer is the same one we hear a lot. I wrote. I wrote all the time and I never gave up.
A good lesson there. Maybe we will write and not make it or maybe we will make it. If we give up and write nothing though? Then the outcome is pretty much guaranteed.