I realized I locked my forum thread and hence couldn't reply to your comment there about the "coloured light effect" in my work.
I'll let you in on a little secret... Sometimes I just put a very transparent coloured layer on top of things and keep painting above it.
That and applying amusing colour correction effects in my painting software once I'm finished. Sometimes if it ends up looking weird I end up painting some more to adjust it again.
We do have a digital medium at our hands, might as well make the most of it ;D