Sterling silver can naturally tarnish with exposure to air, the best way to maintain your silver jewellery is to store it away in a fabric pouch and clean regularly in warm soapy water with a very soft toothbrush and dry thoroughly. You can also use a cloth such as 'Town Talk' silver polishing cloth if tarnishing appears.
Gold vermeil is a thick coating of gold over a precious metal, sterling silver dipped in 24ct gold is what I use. Unlike 'gold plating' which is usually plated over a base metal, such as brass or copper (both non-precious) gold vermeil holds value and can be recycled. Although gold vermeil will not tarnish like silver, it may fade slightly over a long period of time, this depends on how and where on the body it is worn. It is important to care for your jewellery to maintain the gold finish, if ever needed I do offer a re-plating service starting from £20.
Remove your gold vermeil jewellery when showering, exercising and swimming. Perfume and some lotions will corrode the gold coating - always put your jewellery on after applying perfume/lotions. Store your jewellery inside a fabric pouch when it is not being worn.
Solid gold jewellery is very low maintenance when it comes to daily wear, however, avoid wearing your gold jewellery whilst swimming (you don't want to lose it!).
Most importantly, enjoy your jewellery!