Normally airliners have a book that is specific to the airline and the aircraft type called a "runways analysis manual".
You just look up the correct runway and the correct airport, and enter the chart with aircraft weight and wind component. Some operators do not use the advantage of a headwind, but deduct the disadvantage of a tailwind.
It is rare to use full takeoff power, normally we tell the engine its actually hotter outside than it actually is so it give a "reduced thrust takeoff".
Another technique used on long runways in areas where you have steep after takeoff climb gradients is to increase the speed the aircraft while the aircraft is on the runway so we have more energy than absolutly necessary to get airborne to we can get better performance in the event of engine failure.
You may be interested in reading a report issued by the flight safety foundation which takes about takeoff performance.
"Recent revisions of the U.S. Federal Aviation Regulations and the European Joint Aviation Requirements redefine V1 as the maximum airspeed at which a flight crew must take the first action to safely reject a takeoff. Other revisions change the method of compensating for the time required by pilots to take action to reject a takeoff; require accelerate-stop data based on airplanes with fully worn brakes; and require wet-runway takeoff-performance data in airplane flight manuals"
report :
http://www.flightsafety.org/fsd/fsd_oct98.pdf