Please consult a doctor while following this advice.
Keep weight off from the injured area. Crutches and cranes can help some time. Rest is the key to treat strain/sprain. If it is severe, physical therapy might be needed.
Ice helps prevent swelling and pain. Apply cold compress for the first 24 hours after injury.
Compression of an injury prevents aggravation of a swelling. Wrap the sprain or strain in a bandage with advice from the doctor.
Elevation helps reduce swelling. Gravity helps reduce the swelling and relieve pressure.