Actually, my method is alittle more complex, with Science!
First, add the car shampoo (I use about 1/2 strength recommmended since the car is never really that dirty).
Then I add 2/3 full with HOT water slowly, as to not foam the water up, then swirl the water around so the soap disperses within. This allows the molecules of the soap to break up, disperse.
Then I let it sit for 5 min.
Then I take the bucket outside, shoot it with COLD water from the outside hose, this creates a very good head, one which lasts the entire washing cycle! (I prefer Griots Car wash) It also lowers the temp of the wash water to warm.
After washing each panel(linear motion, flip wash mitt, repeat, then 2-bucket method before next panel), a cold water rinse (straight hose, 90% of the water sheds off if the car is waxed, which it is in my case!).
I learned this method from a Professional Detailer that was visiting Griots one day while I was at their distribution center, he spent 30 min. talking of his art of washing his clients $100,000+ automobiles. Very informative gentlemen with a passion for cleaning automobiles! You could tell he takes pride in his work.