Rule 1: Don't be a hero. If someone is willing to take your spot, let them.
Rule 2: Learn the art of subtle queue-jockeying. Eye contact is key.
Body Language of a Queue Jockey
Rule 3: Bring a book. Or a phone. Anything to make it look like you're busy.
Taking Your Place in the Queue
Rule 4: Be prepared to sacrifice your soul for the queue. It's just a matter of time.