I find my favourite lyric videos also incorporate subtle imagery. A great example is the lyric video for "Night Still Come" by Neko Case (linked below). The imagery in the background is subtle enough so as not to distract from the music, but also interesting enough to keep your attention.

https://www.youtube.com/watch?v=qhnFl3Y2FVI

When it comes to what software to use or literal techniques I haven't a clue - but I would love to hear other's personal experiences with making lyric videos, especially having never made one myself.


Cheers,
Deryk