i co own a valetin service dude
Excel valetin (we excel all your expectations) 
.
if you do it right you'll get about 4 cars a day spend around 2-3 hours per car working with you and a co worker. ( most prob be less TBH all depends on how far you are willing to travel to valet a car tbh)
get a business bank account set up so if clients pay by cheque it looks more pro.
get a proper T-shirt made with your company name/logo and phone number on
produce fliers/brochures.
adverts in local paper
making a booking form so the customer can fill it out.
proper recipts
aim not just at cars but at lorry drivers and agricultural vehicles aswell.
dont tell the customer what stuff you are actually using for all you are doing there is basicly saying this is what i use so never book with me again and go and buy the products from the shop and do it yourself lmao.
by shit loads of sponges and micro mits and leather wipes and rubber gloves.
you are just starting out so you dont exactly need a van tbh.
just keep your own vehicle spotless at all times last thing you want is stating you have a company and your car looks a mess.
i have polished/glossed my car twice in the last two days LMFAO whilst in my garage and finishing it at 10pm.
once your company is established you will have to get Uk registerd as a business and then obay by the health and safty rules.you will also have to claim on your insurance that you are using your car for business and now not for comuting.
if you are planning on the way me and my business partner is and looking for a building to use then you will also have to get insurance out on that (public liability insurance) and also insurance out so you are able to drive any customers vehicle with there permission and a signature in black and white.
ther is mroe to the game as alread ystated by cloud with tax/vat.
my best advice dude this is where im lucky my co owner his corsa is LPG'd so we save so much when it comes to fuel its unreal.so if you do get a van try and find one that is converted.
also send out emails to all the cleaning companies
autoglym
mothers
poorboys
etc etc etc
and tell them what your plans are and you wish to purchase there products to us in your company BUT wish to test it out first.
if you type it up correctly they will gladly send you out some sample packs

.
because there wanting your business so will help in anyway possible at the start once you have there trust and they have yours that is when you start to order in the buntch load.companies always work on the aim of the bigger amount you buy at once the more discount you will get.
there aint really anything else i can say tbh.
as cloud has said its not as easy as it seems its slow at first for you are trying to up your profile.
Have you even looked at the other competition you may have around your area?
also seen what products they use or how long they take on a single car?
what type of customers they are getting? (business men or your everyday person)
what type of cars? High spec or your normal ones?
there is LOADSSSSSSSSSSSSSSS and i mean loads you have to think about
our company name took about 3 weeks to think about and thats just the dam name lol.
money wise out of all that i have stated there is this
cost on promoting business
cost on products
cost on insurance
cost on maintance on your own car
cost on Fuel
Managment on your own time