ok so you used linear perspective to add depth. some other good ones are changing values. (aka light in back dark in front or vice versa). texture gradient (aka making those lines on top closer and closer together as they get further away). adding detail when its closer, blurring further away. as well fog makes things look far away.

i have nothing better to add except for that its lookin pretty cool...i like the colors you used

Looks a lot like real paint. I like the veined texture in the dark 'triangle' section especially.