Repeatedly tap X as CJ is falling to take less damage when he hits the ground. Additionally, max out your health bar and get full armor. Go to a high building, such as the one in the Downtown area of Los Santos. Get on the roof and jump off without a parachute in your inventory. When you hit the ground, you will lose most of your life, but still have a small amount remaining. If you have a parachute in your inventory, you will die when you hit the ground. Take a Shamal or Hydra into the second meter of altitude. With a parachute, jump out of the plane and press B to open it. Then, immediately press Y. You will fall to the ground, and if you have full health you will survive with just a little remaining. If you accidentally fall off a very high building, enable the "Spawn parachute" code. Press B to open the parachute and you will drift safely down to the ground.