Or you can be like the idiot I saw once... He waited until everyone was on board and then pitched a fit when he had to gate check his two carryons (neither one of which would fit under the seat)

He had asked the agent, she told him FC had checked in full, but he "knew" that someone wouldn't show up so he just stayed out there until he was "number one" on the list (He told the guy sitting near me that he was 4th originally) When they finally called him by name it was the "get on board now because we are closing the door announcement" No upgrade and no overhead space, just a DYKWIA showing us how to act like a two year old. (He ranted and raved about how as Diamond he should NEVER HAVE TO CHECK MY CARRYONS! LOL!)