Whatever you do never wash cars with washing up liquid, its not good from what I was told :?
Best stuff to use is the Megs Gold Class or NXT Car Wash, they are both excellent and gives a great shine even without waxing, also beeds off water when you rinse and smells nice too
Use that with a Megs wash mit and you can't go far wrong, alot softer than using a sponge so is more kinder to your paintwork on the car.
I rinse(Jet wash preferably) the car off first everywhere to loosen/get off the loose dirt etc... then I wass the roof first, front window, bonnet, rear boot, then work my way down the sides, start with the rear quarter panel first, then from the window down on the door, then I do the other side the same, then the rear bumper and last of all the side skirts. Then I will get an older sponge or mit and go around and wipe inside the arches, under the side skirts, also clean inside the doors and boot lid, then rinse off making sure all the suds are out the nuts and crannies and dry off using the megs microfibre drying towel.
Job done
Carl