We're changing things up a little bit here. We like to talk about fuels and oils and engines, but we also know people like to keep their cars looking like new in addition to running like new. If you want to how to wash your car the right way, you want to talk to the people who do it for a living - the auto detailers.
Be cool - You don't want to wash your car when the exterior is hot. This causes the soap to dry too quickly, possibly leading to the staining of the exterior and more work when you have to re-wash it. So the tip is - wash your car in the shade when the exterior is cool.
Be nice, so you don't wash twice - Use a presoak to help get stuck-on stuff off the extrerior before the main washing. Taking this exterior step will actually save you time by making it much easier to get everything else off during your main wash (that you're going to be doing in the shade). So the tip here is - presoak the exterior.
Treat it to a nice bubble bath - Professionals recommend using a mild soap, preferably liquid, and also using a car wash mitt or a large sponge. These seem to do the best job of cleaning while protecting the car's finish. And use plenty of water - now is not the time to skimp on that. So the tip here is - use mild soap, a mitt or sponge, and plenty of water.
Step by step - Detailers will wash (and rinse) one section of a car at a time. They start from the top and work their way down - roof, front hood, and back, top side panels, then bottom side panels. They start at the top because these are the least dirty parts. So when you rinse the top, you don't rinse all the dirty water onto and re-dirty the bottom panels (that you would have cleaned first if you hadn't been reading this blog). So the tip here is - go step by step and from top down.
Don't sponge up with dirty water - Before you stick the sponge back into the bucket for more soap, make sure you rinse it off. Otherwise, you'll probably be slopping dirty water back onto the car. So the tip here is - Start clean and finish clean.
Some other tips for the exterior include.... clean the wheels and rims with a separate sponge, so you don't transfer scratchy brake dust onto the car's paint job. Dry your car immediately to prevent water spots, with something absorbent like a chamois. And don't splurge on really expensive soaps and chemicals - a good dilute liquid soap is all you need for washing, and there are a number of inexpensive quality waxes that work at a professional grade as well (like Meguiars and Black Magic).
But even if your ride's paint job and finish sparkle in the noon-day sun like a vision of glory, your job isn't finished yet. Now you've got to think about the inside of the car.
Here's what the pros say about making your interior look as good as the exterior now does.
Spot testing - There are a lot of options for cleaners. Unfortunately, there's a lot of variation in interior materials found across the spectrum of today's car models. So spot test your cleaning products to make sure you won't leave a permanent visible reminder that you didn't bother to do that.
Reaching difficult dirt - Move hard-to-reach debris out in the open by blowing it out with your vacuum.
Tools not just for painting and teeth cleaning - The two best tools the pros use for reaching hard-to-clean cracks and crevices are a toothbrush and paintbrush. Keep them both in your glove compartment for when you go to the car wash.
For stuck-on dirt on floor mats, use a stiff brush in tandem with your vacuum cleaner. The brush helps pull out the dirt stuck in the mat fibers.
Extra time for the dirty spots - The pros know the dirtiest spots in the car are the ones that you touch the most. So spend a little extra time cleaning the seat belt, steering wheel, driver's door panel, and gear shift. Also, pay attention to the V-spot of the seat between your legs.
Clean windows on both sides with glass cleaner, paper towels, and then a good buffing with a clean cotton towel.
Be gentle - cars today are made with less durable materials than before. So clean well, but clean gently, and you'll make them last.