Summarize this article:

You can use heavy make-up for this outfit, covering your entire face with thick coats of gray and green greasepaint. Apply large black circles around your eyes, insert yellow fright-contact lenses, and stage blood to your mouth.  Keep in mind that Medusa should be as beautiful as she is horrifying. Apply make-up so that it looks freaky, scary, and very morbid. Use green foundation, As one who lived in relative darkness, Medusa would not have had bronze skin or rosy cheeks. Instead, she would have been fairly pale, with cracked skin that is peeling from her face. Draw attention to your eyes by applying more heavy black eyeliner and black mascara. You can use dark eyeshadow to make your eyes look gaunt, or you could use a bolder metallic shade of green or purple for something a little more subdued and crazy. Use either black lipstick or red lipstick. Go for black lipstick if you want something spooky. To emphasize the more alluring aspect of Medusa, use bright red or deep red lipstick. Apply tooth black out to make your teeth look authentic and decayed. Use facial paint to draw small scales around the top of your forehead, the edges of your face, and along the sides of your hands and feet.  You could also use black or green eyeliner to draw the scales, or for 3D effect, cut scales from colored construction paper, and apply with water and flour mixture, or cellophane tape. Note that this is strictly optional. Even without the use of scales, you should still clearly resemble Medusa. You could wear a large rubber snake around your shoulders or waist, or weave a smaller one around your fingers.  Hold a rubber snake in each hand, or glue using skin-adhesive squares. If wrapping a large snake around you, make it large enough so that it coils around you without needing to be held in place. Flat, gold or beige sandals work best. Paint all exposed skin with green tempera paint (non-toxic). Antique-looking earrings, bracelets, or brooches can be worn, but don't worry about getting too fancy or too gaudy because the Medusa was a hedonistic demon.

Summary:
Highlight your eyes and lips. Add horrifying scales. Carry around other snakes. Opt for simple footwear. Use a lot of jewelry.