Game design document

Have you tried Google? This question is too broad, and the answer too dependent on a variety of factors, for anyone to even begin to address the question in a forum post of reasonable length.

I would advise working in the industry for an established video game developer before trying to strike out on your own, as it seems you're doing. The barriers to entry for top titles are ridiculously high these days. I guess you could try smartphone games, though. Indie developers are mostly doing that.

You shouldn't take my words as gospel. I do have some knowledge of the industry, but there are a few other folks around here who have more experience than I do, and they may drop in at some point.

It just seems to me like you have no idea what you're looking for, and you seem to have done little independent research. That's why I suggested you try working in the industry first. Hands-on experience is often useful.

Yes, I'm not the most knowledgeable about this - but SPMiller is right. You need a position in the industry to make games, and unless you fund a project on your own - which is possible, of course - writing design documents probably won't do any good.

And, from what I understand, design documents are simply textual descriptions of everything that goes into a game. From the macro level of the world building, to how vertex shaders should gleam in orange light.

have you tried http://www.gamedev.net/ or http://www.gamasutra.com/

Most game designers are able to do something else related to the industry. You have to find out what else you're good at, be it programming, scripting, music, sound effects, or art. You cannot go into game development, indie or otherwise, with just an idea or a story and expect people to support you because most likely they won't. Also, a lot of new developers, mainly brand new, hold on to their ideas/stories like precious cargo and don't let go. Just as a forewarning, don't do that.

Also, when you make your first game, make it as simple as possible. My goal is to develop RPGs, but my first game was a break out clone. I'm currently working on my second game, which is my first original game.

Finally, figure out your goals and go from there. If you want to work for a well known company you have to have a degree or enough experience. If you want to go indie have more freedom, but you have to fund it yourself, like me. Depending on what you want to do, school may not even be necessary. In my case it wasn't because can do everything but art and programming (not the same thing as scripting).