Here's How:

1. Get the ice on quickly.
   Icing is most effective in the immediate period following an injury. The effect of icing diminishes significantly after about 48 hours.
2. Perform an "ice massage."
   Apply ice bag directly to the injury. Move the bag frequently, not allowing it to sit in one spot.
3. Don't forget to elevate.
   Keep the injured body part elevated above the heart while icing -- this will further help reduce swelling.
4. Watch the clock.
   Ice for 15-20 minutes, but never longer. You can cause further damage to the tissues, including frostbite, by icing for too long.
5. Allow time between treatments.
   Allow area to warm for at least 45 minutes or an hour before beginning the icing routine again.
6. Repeat as desired.
   Ice as frequently as you wish, so long as the area is warm to touch and has normal sensation before repeating.