Remember - you may be the victim's only chance of survival. You can increase that chance by 40% simply by administering Cardio Pulmonary Resuscitation (CPR).
Check the victim for unresponsiveness by shouting and shaking him/her. If there is no response, Call 911 and return to the victim. In most locations the emergency dispatcher can assist you with CPR instructions. Pulse Location - Carotid artery (neck)
If the victim is still not breathing normally, coughing or moving, begin chest compressions. Push down with 2 hands 2 inches 30 times right between the nipples. Pump at the rate of 100/minute, faster than once per second.
Tilt the head back and listen for breathing.
If not breathing normally, pinch nose and cover the mouth with yours and blow until you see the chest rise. Give 2 breaths. Each breath should take 1 second.
Video used with permission of www.learncpr.org