Shawn
En-Route
So unless your flying big iron when there is no way to get around the guy in front of you, your flight strip gets moved in the order that you called up ready for take off.
Not always when you are mixing VFR and IFR departures...I have been moved many a times off the #1 holding short line position to make way for other departures. I have learned when there are others in the departure area to move into a position where I am ready to roll but not block the taxiway to the runway should I be told to hold short for other departures.
...of course places like FUL or any other field where the runup is not immediately adjacent to the departure end or outside a defined movement area...another call up is always warranted.