Meet them where they are. That's probably the best advice for teens. This card is for my son to welcome him to his teen years. The theme is the same for his party: Modern Warfare 3 (a video game to those in the know).
I started with a background of mica paint that goes on like sandpaper, and added some bronze. Then the aluminum sheeting was embossed, stained, texturized, and attached with screw brads. Then some gears and stringy paper finish off the piece.