Take these measures as soon as your ankle is injured.

• Rest your legs.
• Apply ice on the injured area to reduce swelling. Do not let the ice stay on for more than 20 minutes.
• Wrap the injured ankle with a bandage to avoid swelling.
• Keep the leg elevated to decrease the blood flow. It also helps you reduce the swelling.
• Once you start recovering, try out some balance exercises.
• If the sprain is severe, you need to visit a physician. 
• Follow up with rehabilitation exercises for proper recovery and to reduce pain.
• After two or three days, it is advisable to take contrast bath. Dip your legs first in ice cold water (for 40 sec) followed by dipping in warm water. Do this alternatively for about 5 to 10 minutes.
• When the pain begins to subside you can start walking. But avoid carrying too much weight initially.
• Even after recovery, continue with stretching exercises that will avoid the risk of re-injury.