Before deciding to give new denim clothing a worn, faded look, be aware that a heavy application of bleach weakens the structure of a fiber. If you want a faded look immediately, you limit the life of your garment.
The more conservative way to fade denim is gradually, by adding 1 cup of chlorine bleach to your washing machine each time you wash your jeans, until they are the color you want.
If you are willing to risk fading a new pair of jeans quickly, follow these instructions: wash jeans twice to remove sizing (starch). Add 1 quart of chlorine bleach to a full machine of water, mixing well before adding the jeans. Agitate a few moments, then allow the denims to soak for up to 1/2 hour, checking the amount of fading periodically. Wash the garment and add fabric softener to the rinse.