Jewellery should be the last thing you put on before going out and the first thing to come off when coming home - this way you'll avoid getting getting perfume and cosmetics on your pieces.
Sweat can tarnish your precious pieces, so remember to take caution and remove before doing any exercise and getting in the shower.
Storage of these items are really important, make sure to keep them away from other metals when they are not in action.
Use a lint-free, soft fabric to clean. Avoid using harsh fabrics that could cause the surface to be scratched.