1.I agree about shortcuts, but it's always best to ask for them; and not assume that you'll be given them as a matter of course.
2.Keeping the aircraft clean for as long as is practicle prior to landing, that's a real cost cutter.
3.Keeping an eye on the amount of potable water carried, especially on long haul flights. This weight multiplied by fleet size and hours flown can really have an impact on economy.
4.Ensuring that all the flying control surfaces are in trim, and that you're on the correct side of the drag curve with respect to pitch attitude, aircraft mach number, and power setting.
I'm sure that there's lots more, but it's time for my tea now!