Thanks so much! Yes, I still usually only colour on one layer. However, in the sketch and rough colour stage of a complex background, I make it much more detailed and refined so I don't have to paint over it or clean it up too much later, and so it won't look pillowy. Hope that makes sense!
Oh, I see. Yes it makes sense. I've been wanting to draw and color more complex backgrounds in my drawings, but I'm not so great at it. So when I look at yours I'm like "how can I do that? (*￣m￣)" Anyways, thanks again.