(There are some really useful threads if you do a search for car wash in this section for more info.)
But, for a "quickie" lesson, you should wash your car in the shade or away from the heat. Avoid washing the car when it is warm also.
Next, get yourself a "GOOD, QUALITY" drying microfiber towel made especially for drying off your car. A nice plush wash mitt should be used as well for applying the soap/water to your car. Mind you, these items will cost you some coin, but way worth it in the long run.
Hope this helps out a little bit.