Silver, when exposed to air, oxidizes.
The best way to keep your jewels looking sparkling is to store them in a plastic bag when you are not wearing them. And wear them - the natural body oils keep them from oxidizing.
If your jewelry has tarnished, please PLEASE say NO to chemical dips. Your jewelry will tarnish faster and harder.
The best bet is a silver polishing cloth. Give your pieces a nice shine with this.
Also, a natural and easy solution is to try this DIY idea:
Sprinkle in two tablespoons of table salt and two tablespoons of baking soda. Drop your silver pieces into the water. When they settle on the aluminum foil, they should not be touching each other. Allow your silver to soak for two to three minutes, or as long as five minutes for heavily tarnished items.