I'm not a wannabe fiction writer. I was once, a long time ago, but I reconciled myself to the fact that I don't have the patience, nor probably the talent. I'm a good writer, but I'm not a good storyteller. I'm good at thinking up ideas, and good at writing scenes, but fitting everything together into an interesting plot is beyond me. So just as I'll never open the bowling for the England cricket team, date any of the female members of S Club 7 or Eternal, or discover a new species of animal, nor will I ever fulfil my other adolescent dream of being a best-selling fantasy writer.
When I was a teenager, though, I read quite a lot of books about creative writing, in an effort to improve. Most of these are pretty useless, but two that stood out to me as being well worth reading are Stephen King's On Writing and Ben Bova's The Craft of Writing Science Fiction That Sells. As is often the case, the people who know what they're talking about are genre writers, rather than high-falutin' literary types.
The advice both men had that really stood out to me is this: if you want to be "a creative" of whatever stripe, stop dicking around and just do it. Ben Bova boils this down to the simplest and most efficient statement possible: if you want to be a writer, write. A writer writes. (He may have been paraphrasing Harlan Ellison.)
King's advice is probably more extreme, and it's this: if you're not doing it already - writing every day simply for the love of it - you're probably never going to make it. If you're forcing yourself to write every day, so that it feels like a chore, it's a bad sign. Writers who end up being succesful are very often the ones who simply have to write every day, and it's the not writing that feels like work. (Adam Roberts said something like this once at a reading I was at; when he's writing he often gets into a fugue state in which hours of complete bliss feel like they're passing by in the blink of an eye.)
Anyway, the point is, thinking is overrated. In life, if you want to do something, do it. Writing my PhD thesis taught me this as much as anything: what you create will never be as good as what you imagine, but those 100,000 words aren't going to write themselves, so you'd better pull your finger out of your arse and get typing. I've, eventually, managed to do the same thing with Yoon-Suin: the thing has been written only because I've spent god-knows-how-many-hours sitting down and just bloody writing it.
So to anyone reading this who is thinking of writing a game or an adventure or a campaign setting or anything else, let this be my message to you: if you want to write a game or an aventure or a campaign setting or anything else, then write a game or an adventure or a campaign setting or anything else. It's not quite as pithy as "If you want to be a writer, write", but we can't all be Harlan Ellison, can we?