DO use only the recommended amount of detergent — too much can leave behind a residue, and too little can result in dirty dishes.
DO run only full loads. If the dishwasher is partially full, use the Rinse-Hold cycle to remove odor-causing foods. This is more economical than rinsing dishes by hand, which can waste up to 20 extra gallons of water per load or 6,500 gallons per household each year.
DO use a rinse aid. They lower the surface tension of the rinse water so droplets don’t form. Particularly helpful if you have hard water, they also help dishes dry faster, which can be helpful when using the Energy-Saving Dry cycle or air-drying dishes.
DO dry dishes on the lowest temperature setting. Hotter temperatures can leave spots on glassware.
Do run one cup of vinegar through an empty dishwasher once a month to leave your dishwasher smelling clean and to eliminate food residue build-up, which can cause clogs and strain
DON’T put the following into a dishwasher: acrylic, adhesive-joined pieces; all aluminum; antiques; blown glass; bronze; cast iron; china with metallic decoration; crystal; disposable plastics not labeled “dishwasher-safe”; flatware with bone, plastic, or wood inlays or handles; gold-plated flatware; iron; knives; many nonstick pots and pans; milk glass; pewter; rubber tools; tin; wooden spoons.
DON’T spill dry dishwasher detergent on flatware; it can cause dark spots.
DON’T jam too many pieces into the silverware basket, which can lead them to get scratched.
DON’T mix sterling or silver-plate and stainless-steel flatware in the dishwasher, even when using the Rinse-Hold cycle. A reaction between the two metals can damage both finishes. Since most knives, including sterling ones, have stainless-steel blades, keep them away from other silver pieces, too.
Parts of this article can be found at http://www.marthastewart.com/275152/dishwasher-dos-and-donts/@center/277007/kitchen-design#225586