They normally are dressed in black, wear band shirts, put on shitty makeup, and carry around Hello Kitty cameras to capture their loved ones eternally. They might take take to take a few closeups of themselves so they can add it to their myspace while they're at it.
Normal Person: "He has a girlfriend."
Emo Stalker: 'Why does everyone hate me?!' *runs off to take pictures of her emo crush*