The specifications for mine were... interesting... so after a while of trying to do something that just didn't want to work, tried something different and now am happily nearly done with the pencilwork for mine. 😛 I'm not used to dealing this much with backgrounds, but hey, new experiences.
The way I work is sketching something, then going over that in more detail, rubbing stuff out then adding more detail (and so on and so forth), because if something's going to work for me, it's gotta be from the moment of conception. It means you just might still be able to see pencil lines in places, but it's much better than the long laborious process of tracing paper stuff (which would be necessary for any kind of cleanup process in my case, I don't trust my computer to not have a tantrum and erase my progress if I tried to clean it up properly). How's everyone else coming along? 🙂