Before you consider laying your life down for your fellow man, consider laying yourself down daily in the small things of life.
Our need to be first overrides our sensibilities resulting in the small infractions of life. Stepping aside for someone on the same small sidewalk or pavement instead of fighting for the narrow space could be one.
Walking behind a car at the light instead of in front of it, could save the driver time wasted, waiting for you to cross on foot in front of the car. It might delay you two seconds but it gives you the opportunity to allow someone the advantage over you for a few seconds.
When standing in line and searching for your money, you could step aside for the next person who is ready with wallet and cash. It might hinder your progress but it is worth setting someone ahead to curb your need to be first.
Small things, daily encounters in life are the practice grounds for the laying down of your life if it ever comes up. One baby step at a time.