If you wouldn't put it on your skin you shouldn't put it on your jewelry. Avoid chemicals like household cleaners and liquid jewelry cleaner. All you need is a great polishing cloth. I love the Sunshine Cloth. You can also clean your stones with a soft toothbrush and water + a drop of dawn soap, then rinse under the faucet and dry with a soft cloth. Don't forget to plug the drain first!
Avoid letting your cat or children play with your jewels.
I know it's hard because they are so cool. Please don't wear them in the pool, as the chemicals with oxidized your metals.
I'm super lazy too, but try not to sleep in your jewels, garden or work out.
Store your jewelry in a dry place. Moisture leads to tarnish, ah hem.. don't store your jewels in the bathroom!
To slow down the natural tarnishing process, I suggest a small ziplock bag if your are going to give your jewels a break for more then a few days.