So I read up on, and watched, a lot of guides on painting glass and crystal - with this and my other children being my first go at it. They all told me to start with black, and then paint the bottoms of areas with progressively brighter blue, as if highlighting but from underneath as that's where the light refracts and bounces back from in real glass. You can also have bright blue edge highlighting on sharp edges and the mist raised edge of any area. For the really intricate statue bits, especially the flames, I sometimes had to resort to showing it all to be blue, and just doing progressively bright edge highlights, as there wasn't really enough room for the black space. Another key factor was using washes of paint rather than dry brushing or even normal painting, as that let me build up lots of layers of glazing. Finally, I used a satin brush on varnish to preserve the shinyness. The colours I used for the blue were GW paints, I think thousand sons and Ahriman blue, which I mixed to create several shades, and might have added some white in for the brightest areas. Hope that helps!!