I use pencil tool to draw the smoke and fire and combine it together. Then i gradient it with smoke and fire colour. Lastly, i make it blur, so it looks like smoke.
After that, I make an earth by using elipse tool and for the land part i just simply draw a shape and put on it. Then, i put some star on the top......
First, I create the background by using gradient tool. Then i use pen tool to make the factory and drop shadow. Also, for the window i use rectangle tool to make it.