Press the clutch in all the way with one foot while pressing the accelerator peddle down with the other foot, raising the engine RPM to a constant moderate level for the first launch around 3500-4k. Lift up on the clutch peddle to the point where the car is just about to start moving and hold both peddles still. Slowly release the clutch while quickly applying the accelerator peddle enough to launch the car quickly, but not too much to induce a large amount of wheel spin. Start conservative with the first launch and keep increasing the RPM at which the car is launched at during the subsequent runs. If the car starts spinning the tires too much after the launch, lower the launch RPM and try again.
Lots of practice required to keep from frying the clutch or bogging the motor