Training Your Fine Jewelry:
The first thing you should do is to give your fine jewelry its own little space for when it is not being worn and train it to stay there. Jewelry items do not live or party well together. Much of the damage, other than wear, that is done to jewelry happens in jewelry boxes. Stones scratch each other and the metals around them. Chains get caught in tangles that almost always cause some sort of damage.
Cleaning Your Fine Jewelry:
The best way to clean your fine jewelry is with a soft (used) toothbrush and a mild dish detergent. If the pieces are very dirty, you can soak them in detergent and water. Do not use harsh cleaners such as chlorine bleach or ammonia. It is not advisable to use toothpaste either. Many contain a mild abrasive, which will remove some metal and cause a dull finish. Any competent jeweler can polish items on occasion, but this process also removes small amounts of metal and so should be used sparingly.
Checking Prongs & Stones:
If the stone moves in the setting, put it in some kind of small bag or container and take it to your nearest qualified jeweler. The small bag prevents loss of the stone should it fall out. Loose stones are also more easily chipped or broken. Another good indicator of a loose prong is if the piece gets worn in clothing or hair by a prong.
Checking for Wear and Tear:
Over time, gold and silver will wear down. This can happen over months or years. This can be a problem for people who do certain kinds of work. The solution to this type of problem is the use of heavier metal in the prongs, the use of platinum for the setting or the use of a bezel setting to secure the stone. Prongs should be checked occasionally and if thin they should be replaced. The bands on rings can also become quite thin and ever need replacing. The thinner the band to begin with the faster this will happen.
If you give your jewelry a little care and check it periodically for wear and overall condition, it will give you many years to a lifetime of joy. A competent jeweler can recondition most pieces so long as the damage has not been allowed to go too far.