(The following is taken from a blog post I made in December 2009, responding to a comment asking how I made playlists and soundtracks for writing.)
At this point I’ve become a bit more systematic about it, so here, in case it’s useful to anyone else, is my system.
Step 1, way back in the day, was rating all of my music. This was, to be honest, a giant pain; I had about 6,000 songs when I set to work, and it took a while to get through them all. I’m very glad I did it, though, and even more glad I didn’t wait any longer to do it.
Then, if I recall correctly, I went through everything rated three stars and higher and created a bunch of mood-related playlists: bright, creepy, romantic, triumphant, etc. I mention this becuase maybe it would be useful to someone else, but the truth is that I’ve only rarely made use of those lists. Slightly more useful to me have been the “style” and “regional” lists; I’ve got one for all my Asian-sounding music, for example, and one for stuff with lots of drumming in it, etc.
When I’m making playlists for a book, though, what generally happens is I go through my list of albums and dump suitable material into a “reserve” playlist. I did this first for Memento, the game I ran, and it proved to be a godsend, so I’ve kept the habit since. Usually there’s some criterion guiding the formation of the reserve; in the case of Midnight, for example, I was looking for dark-sounding orchestral music. I didn’t want anything too modern, because of the period, and (with a few exceptions) I didn’t want words. Whenever I get around to writing The Changing Sea, it’ll be ocean-related music: the Pirates of the Carribean soundtracks, Master and Commander, sea chanties, whatever.
The reason for this is that I need some limitation. I’m up to over ten thousand songs now, and if I don’t find some way to narrow my field of selection, I’m doomed. Once I have my reserve, though (which is usually hundreds of songs all on its own), I sort them into playlists to actually listen to while writing. In the case of an Onyx Court book, there’s usually one for the faerie court (dark and atmospheric), one for the mortal world (whatever was current at the time), one for romance and sad things (the fact that I combine those two might be a telling point), one for battles, etc. And then I put those things on shuffle while I write, picking whichever list suits my immediate purpose best. This means I get variety within the parameters of that night’s scene, which is generally useful when you’re going to be listening to this stuff for months on end.
When it comes time to actually make a soundtrack, I figure out what characters and events I want to assign songs to, and then I make a whole bunch of playlists, one for each track. That way I can go through the reserve and toss possibilities into the relevant lists. Sometimes I work from the mood lists instead (Baroque music for some things in Star, for example), but more often I just cull through the reserve, since usually I’m doing batch jobs, looking for a bunch of things at once. Mind you, sometimes I just pick a song without any searching; it’ll come up on shuffle at some point and I just know I want to use it. But not everything works out that way.
Here’s the interesting thing about the process. Some authors, as a revision tool, outline their book after they’ve written it; that helps them figure out just what they’re doing with their story. This? Is my equivalent. Deciding what deserves to have a song, I’ve realized, is a form of outlining, and then the actual selection of music forces me to think about what exactly I’m trying to convey. This is somewhat true of the character-related selections, but especially true of the ones that soundtrack specific events; I use a lot of film scores, which means I’m listening to various pieces trying to find the one that really matches the arc of that scene. No, I want something that sounds creepier at the beginning, and then builds in a slow crescendo rather than going loud really suddenly, and then it needs to cut off right after the climax, without a long denoument — I learn a lot about my story by going through this process. And sometimes, yes, I’ll listen to a piece and decide that while it doesn’t match the scene I have, maybe the scene would be better off if it were more like the music. Mostly the soundtrack gets matched to the story, but not always.