On a serious note, a trick that learned from some Ferrari/Alfa owners years ago, is to add a drop or two of Olive Oil to the wash. I know it sounds ridiculous, but if it's just the right amount, it keeps the soap from stripping the wax, and it actually "feeds" the paint. Not something that I found works on dark colors though.
That works on Italian cars, but German cars prefer beer.
I like to hear everyone's preferred washing methods. Like mine, they're a combination of experience, science, and voodoo magic. And with a hard-to-keep-clean triple-black, I need all the voodoo I can get.