Quote:
Originally Posted by
Journeyman 
I used to fly between Australia and Japan a few times a year for work and family purposes and I was only upgraded twice in about five years. Then, prompted by a friend of mine, I started asking.
Once I started asking - basically just smiling at the check-in person and asking if there were any spare seats in business or first class - I was upgraded about 50% of the time. On one occasion, when I asked if I could be upgraded, I was told that I had already been assigned to business class.
Most of the time I wasn't wearing a suit, but I was neatly dressed in chinos and a button up shirt, which was more than could be said for most of my fellow passengers.
Helps if you are traveling alone. While in college, I got bumped twice from Osaka to US, because of overbooking. First time they bumped me up but I got bumped back down because I asked for a special meal.
Since then I stopped asking for meal request.
I agree with dressing nice. Tattered jeans/t-shirt, dirty sneakers isn't going to help