A strategy is, to be unique by asking a specific question, and have a plan for following up. Your objective should be to build an advice and guidance relationship with the celebrity because he/she can give you tips on how to get where you want to go faster.
Another tip, is to watch what others do. When the celebrity steps off the stage to greet attendees, watch what people do wrong (infringe on personal space, not taking NO for an answer, gushing like a fan, etc.). When you see what doesn't work, you'll feel more confident about your professional approach.
For more tips and articles by top entertainment industry career coach, The Greenlight Coach, visit www.TheGreenlightCoachBlog.com