Use a Quality Shampoo*: I really like Pinnacle Bodywork Shampoo, but econimally I like Maguires Gold Class Shampoo. It's the one Jason uses. In either case make sure you use one that doesn't strip wax (according to it's directions) and that you don't use dishwashing liquid.
Clean Your Wheels First: Clean your wheels and tires first (I use Eimann Fabrik's Hi-Intensity cleaner), wet down a cool wheel and spray on a small amount of EF Hi-Intensity on the wheel and tire. Let it sit for one minute on the wheel then agitate with a foam brush. Then take your tire brush and scrub the tires clean. Then rinse off with a heavy stream of water.
The Two Bucket Method: I use the two-bucket method to wash cars. One bucket with just plain water, and the other bucket with your favorite car wash shampoo (my favorite is Meguiars Gold Class Shampoo.) Also get a quality 100% cotton chenille mitt (Viking from AutoZone.) If you are really picky get two wash mitts so you can have one for the top half of the car that stays cleaner than the bottom half of the car.
Wash: Fill one bucket with clean water and shampoo to the other bucket and fill with a heavy stream of water (mix per instructions on bottle.) Spray down your car to get it wet. Start washing the top of your car using front to back motions, then rinse the mitt in the bucket, re-soap in the other bucket, and wash the hood, then rinse the mitt, and re-soap, wash the trunk and windows of the car, rinse in the rinse bucket. Now spray the car down where you just washed. Now empty out the rinse bucket and refill with clean water. Grab your other mitt and wash the vertical panels, rinsing and re-soaping after each panel.
Rinse: Now remove the spray nozzle from your hose and let the water flood the car. This should make the water sheet off and minimize drying time.
Dry: Now dry the remaining water on your car using a synthetic chamois like the absorber (K-mart $10) or the water bandit from www.kleanride.com follow up the missed spots with a Microfiber towel and open all the doors, the trunk lid, the hood and gas cover. Take a terry cloth towel and dry off all these areas of the car. Close the doors, hood, trunk lid, and gas cover. Take another terry cloth and dry off the wheels and tires.
Inspect: Your car should be clean of loose dirt and contamination.