Well, my dad works at a bus garage, so I go up there and wash my truck...
they have a wash bay with a pressure sprayer, so first I spray down the truck (with water and soap) and then I scrub the truck down with a brush they have there (very soft bristled) and then I rinse it off with the pressure sprayer...
after that, I shamy it all off and make the tires look like they're wet...