An upgrade is like winning a lottery in the air travel world. No one can tell for sure the proven-way to get an upgrade every time. However, it certainly helps your case if you are not a rude person. Things that can strengthen your chances of getting an upgrade are; you are extremely tall, attractive, well-dressed, pregnant, or a friend of the flight crew. And hey, always try to be nice to the flight crew. According to one anonymous flight attendant, getting an upgrade to first or business class is still possible even after the cabin doors close. However, it doesn't often happen a lot. Still, who knows you might hit the jackpot someday.