I started with the idea of just trying to play with the original poster art but wanted to make it my own. I and needed to make the LAPD flying car. I got a stock image of a car and used parts to make a car.
Then I drew the building in Illustrator, and added texture and colour in Photoshop. 
I got some brick and glass brick image textures from - (textures.com).
Then I painted Leeloo in photoshop, I'm still learning to draw on the computer
but I don't think it looks too bad. 

I then added everything together and added more texture, smoke and some lens flairs.

Then to bring in the Cyberpunk I added more texture and smoke, rain neon lights lens flyers colour overlays.

I like it. Let me know what you think. :)