Utensils can sometimes fall through the silverware basket and block the spray arm preventing it from rotating. When this happens, water can spray directly on the door causing the dishwasher to leak. Take a look at the bottom rack before starting your dish washer to make sure nothing will prevent it from rotating. Check and clean the spray arm. You should also make sure no pot handles extend below the dishwasher rack causing the spray arm to be blocked.
Hot water is also a requirement for cleaning.
Test your hot water by placing a meat thermometer in a mug. Turn on your kitchen tap to the hottest setting and run water into the mug for two minutes. If the temperature is lower the 120 degrees you need to raise the setting on your hot water heater. If you have never cleaned your vent line brushes are available at most hardware stores for a few dollars. You should clean the vent pipe at least once a year.