Not wishing to cause offence, but if you are going to offer valeting, you don't want to offer a basic hand wash, and then a polish...
Are you going to do any paint prep? What wax or sealant are you going to use after a polish? What about trims, wheels, arch liners, glass, rubbers, soft tops, bright work etc? You'll need different products for different paint finishes too, even down to the colour! Do you have facilities?
There is a massive difference between washing your friends' cars with a better product than they usually use, and valeting cars. There is also a big reason why I don't do many valets, 95% of my work is detailing...most people that really care enough are clever enough to go to halfords and buy some decent cleaning gear, those that don't use the £5 wash in the local supermarket carpark. Some people go to so called valeters, that think it's easy money and offer a machine polish for £30, and then go to people like myself, to correct the damage caused.
If you are serious, then good luck with it, but do plenty of research first
