Sooner or later, everyone is going to experience an ankle injury. What you do with that injury could make the difference between an ability to function normally, and a lifetime of chronic pain. The very first thing to remember (even before going to the doctor) is R.I.C.E.

REST: Rest does not mean that you should do nothing with an ankle for days or weeks on end after injuring it. It means that after you sprain your ankle, you need to get off of it right away to prevent further damage. It may mean you need to lay off of sports for a while or get a pair of crutches for a few days. Just remember, studies on football players have shown that injured players who stand on the sideline to watch the game (instead of sitting down), take almost twice as long to get back on the playing field post injury.
ICE: This is a critical step in the healing process. Ice is a vasoconstrictor (as opposed to a vasodilator). In English, this means that ice “constricts” arteriole blood flow at the site of injury and slows down inflammation. Inflammation, contrary to what most people think, is the release of the chemicals that used to be inside of cells, into the extracellular fluid once those cells are injured and die. The inflammatory chemicals attract the fluid into the surrounding area and cause swelling. Some swelling and inflammation is a good thing and actually promotes proper healing. However, too much swelling causes, among other things, a build up of scar tissue. I strongly advise not using anti-inflammatory drugs to deal with swelling because they have been scientifically proven to cause injured ligaments to heal 1/3 weaker, and about 40% less elastic. Not good for preventing recurrence!
COMPRESSION: A bandage or ankle “sleeve” will suffice here. This simply helps keep swelling down.
ELEVATION: Elevation helps keep swelling down as well but only if your ankle is elevated above your heart! Simply propping your foot up in a recliner is not good enough.