Well, I haven’t started that many projects - one, a decade ago, that never went anywhere, and two, my current WIP.
When writing prose, I find that I have to really commit. What’s finished is more a matter of what I stay interested in than what is good. So with my current project, I have promised myself to continue working on it until it is done, and not start any other projects that would suck energy away from it.
Of course I give myself free reign to jot down ideas.
When writing music (with the kind of music I make, ‘writing’ is sometimes the wrong word, but whatever), I go through tons of ideas, and throw most of them away. The ones I finish are the ones that won’t let go of me - that happens with music in a way it doesn’t with prose.
As for the process, I had a devil of a time getting started. I came up with a premise and an opening text pretty easily - it popped into my head as a result of a discussion. But then I had this situation - the protagonist has a seemingly intractable problem. To finish the story, I have to come up with a solution. So I brainstormed for a couple weeks (maybe more) using a tip from Jim Aikin about switching off the inner critic. While I was doing that, I coded up random things for the game’s opening that might turn out to be interesting.
Eventually I came up with an ending I thought would be satisfying and then started thinking about what should come in the middle. I developed a couple puzzles based on the protagonists needs, and a couple based on what I thought would be fun given the environment he was in. Then I spent several months trying to implement all that. As a programmer, I took it as a point of pride that NOTHING should be impossible to implement, as long as I could completely visualize the way it should behave. I still stuck with what I thought were reasonably modest goals but…
…along the way I got sidetracked by writing extensions. I still feel like writing extensions is progress, but I think I’ve thrown away about 3 out of 4 extension ideas that I’ve started. So in that sense I guess I do have “trash” that I write and discard.
I also ended up throwing out a lot of the game’s opening, which was coded before I was really sure what direction I was going. I think it was very valuable for helping me get started, though. Right now I’m in alpha testing and I’m starting to think throwing away more. We’ll see how it goes…
As for details, I’ve tried to at least write room descriptions as I go. But there’s been a lot where I’ve said “I need to just write SOMETHING to get past this block. I’ll deal with the details later.” And then I’ll have detail-sweep days where I just pick up stuff that got skipped over earlier. Alpha testing has been a great motivator for this.