Few things to take care of silvery jewellery.

Avoid exposure: Contact with household chemicals, perspiration, chlorinated water or any substance which contain sulphur will cause corrosion and tarnish, so its good idea to remove silver jewellery when doing household work.  

Storage: As exposure to air tarnishes it, storing silver jewellery in airlight container is a great preventive measure.  

Polishing: Simply polishing your silver works well when the tarnishing is not too severe.  You can use a silver cloth to polish your items.