Minimize your jewelry's contact to chemicals (lotion, hairspray, bleach, perfume, etc) to best maintain its shine. Avoid wearing while swimming in a chlorinated pool.
To store your jewelry, wrap clean, dry jewelry in a dry, soft cloth and keep items separate to prevent tangling and scratching.
Sterling Silver Jewelry
The best way to prevent tarnishing (oxidation) when not wearing your sterling silver jewelry is to store your clean, dry pieces in a dry, airtight container or Zip-loc bag and keep items separate to prevent tangling and scratching. Avoid leaving your jewelry in that bathroom, as the moisture will speed up the oxidation process.
To clean your sterling silver jewelry, use mild soap and water, or a sterling silver jewelry cleaning solution, followed by a sterling silver polishing cloth. For stubborn tarnish, Tarn-X works well, but be careful to follow instructions, don't leave jewelry in the solution for long.
For items that are not highly polished, a paste of baking soda and water can be gently rubbed with your fingers or a soft bristle toothbrush to remove tarnish. Rinse well and follow with polishing cloth. This method isn't recommended for very shiny jewelry, as the baking soda is slightly abrasive and will dull the finish.
Gold Filled Jewelry
To clean, mix mild soap, a drop of ammonia, and warm water. Gently swish the jewelry to clean, and then dry with a soft cloth (non-abrasive), and let it dry thoroughly. You may also use a jewelry cleaning solution, followed by a jewelry polishing cloth.