In order to preserve your jewelry be sure to always keep it clean and dry. For the longest lasting look it's best to remove it before swimming, bathing, or applying cosmetics or perfume. All silver will tarnish over time and exposure to moisture will accelerate this process. Storing in individual zip lock bags will help protect your jewelry.
Please note that tarnishing may occur due to the natural oxidation when certain metals are exposed to air. To remove tarnish simply clean with an anti-tarnish jewelry cloth.