Well, it starts with a general plot idea. If I'm serious about the project, I roughly follow these steps...
Step 1: I figure out the kind of gameplay I want, followed by some eventing to create said gameplay mechanics. I find it is much easier to write a story when I know how it will fit with the gameplay.
Step 2: I write the script (as in the dialogue). Writing is a passion of mine, and I've found it simply does not work to write the dialogue in the editor. I use Final Draft, which I would recommend to anyone. The demo version is free with all the features included. The only limitation is that you can only save documents of 15 pages or less, so I just save the script in segments, which actually helps later when I polish. Currently I have one project with over 80 pages of dialogue, and another with maybe 20.
Step 3: Put it all together! Actually, I try to recruit people once I hit this stage. So far I haven't had the best of luck... Speaking of which, you can check out one of my current projects
here if you're looking for a solid game to contribute to.
Step 4: Polish
everything! ;-)
-flap