I went to a goth event today where the theme was futuristic/cyber. Here's one of my accessories I made for the outfit. I also made goggles, which have a tutorial as well.
Find your dust mask. I forgot to take a pic of mine before I started but here's what they look like.
Find the picture you are going to pain on it. Print it in the exact size you want it.
Here's the one I used.
Cut out the black parts to make a stencil and use it to draw the design onto a mask with a pencil.
Paint the design onto the mask.
When the paint is dry, paint the rest of the mask.
When it is dry, just fix up the symbol if you accidentally painted over some of the lines and then you're done!