Chaos Shrine (Terrain / Tutorial)

As being a bit eager to get my "Dark Vengeance" Box from Games Workshop I already did some hopefully fitting terrain piece for the gaming table.

This is the actual project.. a shrine to the evil eye supposed to be used with Warhammer 40K.
Things used: old Styrofoam from the TV set, cardboard,ash from the last bbq, Styrofoam glue , Styrofoam coating (white), Acryl colors "Lakritz", two different grey shades
purple , two different red , light blue and white
As this is my first project and first piece of terrain I would be grateful for any hints and suggestions.
What happened by now:
Cut the Storyfoam into desired pieces with cuttings etc. ,Cut out the eye as well as the two stripes (going up and down) ,Glued all things to a cut piece of Styrofoam, Undercoated it with Styrofoam coating,Painted the whole stuff black and let it dry,
Drybrushed with the two grey colours,Drybrushed with watered ash from the last bbq
Painted the eye and stripes purple, drybrushed in two different shades of red
Painted white and blue.
Thats what happened by now..