what seems to work best for me is I first create the first level. i think of the things that happen in that level. (like soliding platforms in Codename: Paperboy). then i figure out how this could be used in-game (like going through the level while getting the right items in the right order). then i ask for others opinions on how they think the game would turn out like. (in my case, asking my sisters or posting it here). after getting opinions, i start on the next levels and in some cases a demo level. usualy these are in "primitave graphics" but change later on. then i start composing music (or find music online) that go with each level. Finally i update the graphics to match the first level (though by then, in Codename: Paperboy, i would have changed from the SHFL graphics). then i test the game out with others tjo see if i missed any "bugs". then i put all of the file together, zip them, post it, and release it. then it's done.