How to maintaince?
Avoid chemicals (e.g. hairspray, household cleaning products, perfume)
Don't shower or bath while wearing your jewelry
Minimize exposure to sweat by removing jewelry before exercising
Giving jewelry a gentle swipe with a soft polishing cloth to remove oils
Store jewelry in a soft pouch, acid free baggie or other dry spot.
You may even wish to purchase a commercial anti-tarnish pouch or strips to store with your jewelry.
Remove jewelry before going to bed to avoid potential damage, snagging, etc..
This is a weird one, but avoid contact with most wood (unless a box is specifically designated for jewelry) A lot of wood can contain acids that can cause jewelry to tarnish.