DIY Halloween Costume Idea – Pin Up Girl. Dressing up like a Pin Up Girl is a classic do it yourself Halloween costume. In a nutshell, the look is sexy, glam, and it can bring out your sultry retro side. This type of costume also leaves tons of room for creativity, so you can adjust your pin up look to your overall style. To pull off this look your hair is very important. You can create a hairstyle that features pin curls, or a retro pinned updo. Be sure to pair you look with red lips and long lashes. Look below for a few more ideas you can use.