Normal oxidation from air will occur on natural products. Minimise by storing in a dry location, preferably in a cloth bag or jewellery box, separate from other jewellery to prevent scratching.
Store away from heat sources, direct sunlight or in vehicles. Protect jewellery from moisture and don't wear jewellery while bathing, showering or swimming.
Body products, make-up and hair spray can contain chemicals that may damage your jewellery so it's best to apply them before adding accessories to minimise damage.
Avoid hard knocks, heavy pressure and take care not to bend jewellery.
Clean with a soft cloth, or silver cleaning cloth for sterling silver items. Do not submerge in water.