Perhaps a lot of writers do this, but there are some scenes that as I write them or rewrite them, a song pops in my head. From that point forward, every time I hear that song, I think of the corresponding scene. Occasionally, a song will just remind me of a whole book, either matching in tone or forever tied to a memorable lyric. If I’m lucky, in the middle of edits I’ve got a song I can play for inspiration that invariably makes the scene better.
For example, I can’t hear Linkin Park’s “What I’ve Done” without thinking of Scorched. The lead character in that book, call her Missy or Kallista or Kat, has quite a past. The tone of What I’ve Done and the lyrics fit her predicament perfectly:
I’ll face myself to cross out what I’ve become
And let go of what I’ve done
I also think the song has a bit of a dystopian or darkly urban vibe, which also fits the book.
On the other hand, many of the songs I associate with specific scenes in my military scifi books are instrumental. If you watch TV, you’ve probably heard music by Two Steps From Hell. Their work has been featured in ads for blockbuster movies as well as commercials. They are a great source of inspiration for starship battle scenes or poignant life-or-death situations.