I would say your going on pretty much on the right tracks, what I have done is A, had a great idea for a game that I would like to see and that is reasonably newish in terms of idea's, I say new cause I havn't seen anything like it anywhere to date, so I am now B, (in sparadic instalments) bringing it to life in terms of an actual concept and am outlining the main tasks the game should perform how it would hopfully play or so far see it playing, and am now C, detailing it in the best way I can through revision of the certain area's it covers, like if it was a football game I would revise the intimate things of football for instance, I now D, start making and testing some of the more strenuous ideas that may be hard to deal with, here I am working on little test programs to do things like bulding the levels and how many levels will this thing take before being too repetative etc etc.. sorry a little vague but I have to conceal this idea too for the time being, but the tests help to desifer what you definatly can do, what you possibly can do and what you probably can't do and the test I do are really basic versions of what I might have done or might do if it works/would have worked (this saves lots of tiem down the line).. once I test a certain aspect that works, I deal with tuning it up and getting the areas related to the test written out in detail in a near as I can make "design doc" which probably looks like most peoples scrap books, but it works for me, and I get teh basic outlines for such things like design docs from kind poeple around teh internet that have given write ups on such things at places like the programmers vault or doctor dobbs as it is now known, gamasutra and other such places worthy of programmers worshiping time
As far as the actual final building of the game goes I would never beable to do it alone, so when I see poeple offering services on see offers of interest in certain areas here on teh forums that I think may like to help with this project down the road, when I am ready to have help with it in their area of interest, I contact them and let them see an outline of the idea or concept pages of the idea and see what they think, some reply and some don't, I let them know it may be a while until I need them but then I get people that are plain interested responding and hopefully will end up with good help, help that I can call on when the time is right rather than having 20 of us sitting round making a mess of soemthing that needs time to cook up properly rather than too many cooks to help burn it.
hope this helps, sorry if it doesn't
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