Silver and gold jewellery can be cleaned with a silver cloth, these can usually be bought from a hardware shop.
Try to keep your jewellery in a jewellery box, or gift box to avoid scratching on other items, and to prevent the silver tarnishing.
Try to avoid direct contact with perfumes and lotions, these can affect the lustre of your jewellery.
Seaglass jewellery can be gently rinsed in soapy water if it needs cleaning, and allowed to dry naturally.
My Seaglass jewellery is made using pieces of glass washed up on the Cornish shoreline, usually collected from around the St Ives area of coastline.