For a sprained ankle, use R.I.C.E.
Rest - Rest laying down
Ice - Use an Ice pack on the afflicted ankle
Compression - Use a compress
Elevation - Use pillows and/or folded up blankets to elevate the injured foot
For other afflicted limbs, use the same techniques, although elevation may not be needed.
To make an ice pack at home, add 2 parts water and 1 part rubbing alcohol (70%) to a washed-out personal or 1-liter soda bottle. Make sure there is space in the bottle.