Speedy procedure no 11. - Ensure that the cabin tell you they're ready for departure before you tell us that you are.
Speedy procedure no 12 - If you're likely to miss your slot, don't wait until ETD + 9 mins to tell someone, sometimes we may be able to help, sometimes not, but it's a guaranteed method of being refused pushback / taxi clearance if you keep quiet.
Speedy procedure no 13 - Don't tell untruths to get pushback clearance ahead of someone else, (i.e. no tug attached, no ground crew available etc), this is becoming an irritatingly common practice, and achieves nothing other than problems for ATC and other's on the ground and in the air.
In our particular case, because of taxiway weight restrictions, we have to give extended routings to arrivals to allow certain aircraft to taxi and back track the runway. This plan kicks in from the moment we know you are ready for start, any deviation can lead to significant delays.