Hatchet Harry,
Stupid question perhaps but I ask myself how I can work harder?
Every pilot in my airline gets his roster and works accordingly, therīs no way of affecting the amount of duty. The only way I see is by working on your days off.
If you work hard by selling your days off, your reward will be money and thatīs it. I donīt think it should qualify for earlier promotion. Everyone gets his shot at it when itīs his time.
(Iīm absolutely sure you donīt mean working harder by taking less fuel, accepting aircraft of questionable servicability, going below minima etc, though the bean counters and managers at some airlines would certainly love that.)