Silver will tarnish over time and this is a natural process caused by oxidation.
When cleaning your silver it is recommended that you use a mild soap and water solution and pat dry. Professional polishing cloths can also be used.
Do not use silver cleaning and tarnish-removing dips, especially as many of these pieces have decorative oxidation and using dips could remove this altogether and discolor pieces.
Do not wear your piece while bathing, swimming, doing dishes, cleaning with chemicals, or anything else where the jewelry would come into contact with abrasive soaps, sea water, chlorine, or chemicals.
When you are not wearing your silver pieces, store them in air sealed bags and in a cool dry place.