I love what you did with the purples in colored pencil. The crystal and the title text look translucent and glowing - as they should! (Don't look into the beams for too long, though.) It looks like you got a pretty good scan/photo, too, so I don't think you have an issue with lighting. To punch it up, you might just apply more pressure for deeper saturation in the greens, browns, and tans.

You could also always manipulate the hand-colored photo in Gimp, to add saturation, modify hue, or even brush in more bright colors.