I have own a Silver ring for my wife and now it starts tarnishing?

Well the basic cause of jewelry tarnish is the presence of Copper which is present in the Silver jewelry which react to the oxygen in the air and cause silver to tarnish.

The best and the easiest way to remove the tarnish is using a specially treated polishing cloth (such as the Sunshine cloths available at Aquablue) and the sterling will look brand new again. I hope this will help you.

All the above methods are correct and appreciable. You can do so at home, but I would suggest you that since the ring is special to you and it has already tarnished badly, at first place you should think of getting it removed from a professional person. Once, it is gone, you can ponder over taking care at home.