My all-time best bump with the highest payoff was EWR to MCO on a Friday evening in the summer. I was first given two free tickets from CO (anywhere in the US, Mexico, and Alaska) good for two years. They also gave me meal vouchers. An hour later, I volunteered again, getting yet another free ticket. I finally made it on the last flight that evening but when I got to Orlando, all rental cars (at least the economy ones) were gone!

More Tips

Go on a Friday or before a holiday.

Specifically book flights that are oversold. It is first come, first serve on the day of the flight.

Leave yourself extra days to get to where you are going.

Tell everyone around you that it is such a terrible deal so that noone else takes the bump and the stakes get ever higher.

Lastly, wait until the end of boarding to get on. Many times, I get bumped because I am the only one left out there and a last minute business traveler will not take no for an answer - they are getting on that flight.