Wear a long, poofy dress and red lipstick (make sure the lipstick gets on your teeth).
Wear white high-tops like Converse All-Stars under your dress. To make the high tops show, hold your dress up when you walk.
Now put a tiara crooked on your head. Slouch a bit when you walk. Last, don't say please or thank-you........except when they give you candy.
Thanks to Stephanie for this idea!