Sort and reverse. You can't mix colors if you expect them to stay the color they were the day they came home with you Keep your whites, darks and neutrals in separate wash categories. Turn your clothes inside out. The fibers being directly tussled by your machine's agitation will be those on the "inside" of the garment, to save the look of the outside when you wear them.
Keep cool. The idea that clothes get cleaner with hot water is a myth. They get just as clean with cold water in the washing machine. Not only that, but they don't need the highest heat setting to dry. It will take longer, but if you reduce the temperature of your dryer, you'll see less fading over time.
Go green. Detergents that are hypo-allergenic or safe for the environment are free from the chemicals that most commercial detergents have. These chemicals are harsh on your clothes and lead to fading. A fragrance-free, dye-free, "green" detergent is a good buy.
Let your washing machine fill up halfway with water, pour in your detergent and 1 cup of white vinegar, which prevents fading.