I start with a backed out tank and do just the most basic layout of what I want.
Now I crudely white the wizard in. It's important to work in layers to build depth.
Now I add some cool crosses, skulls and congering clouds of blasphemous evil. You can quote that....
I roll the clouds up to tie the two tanks together. There is a dragon on the other side.
Now I take some candy red and and some solid red to help build and start layering it in. After the background I add dark blue to the mix to do the shadows of the robe.
Now some pearl white and yellow to come out of his (it's) arms. The pearl it to have it glint in the sun.
More color with yellows, blues, and purples. I add some more details. At the last moment, I see that the vortexes look like eyes so I decide to make a hidden skull in the background.
All cleared and ready to go... The actual tank is much sharper than this but my camera overexposes the whites... Hope this helps. Don't be afraid to try new stuff.. It's only paint.