Start at a chevy/ford/dodge dealership. Work there for a few months. Then go to an import dealer for a month or two. Then move up to a higher-end dealership, and finally to a private detail shop that takes client work.
I don't know how many guys who come to work for me that I get that:1.) think they either know everything (but don't), 2.)don't know what they are getting into, or who 3.)just don't want to put in the time needed to really learn "the business".
If my plan of action sounds like a lot of time, you are right. And that is just the beginning. It takes a long time to gain true experience. You gotta put in some time, you gotta pay some dues if you want to start your own business, which is what I assume you want to do.
And guess what? If you try my plan, you are likely going to run into guys who are not willing to teach you! With detailers, time is money. It will be tough to find anyone willing to show you (in their eyes, waste their time) the ropes.
My advice is to go to the smaller dealerships, where you will not be one of 15 guys who do nothing but wash cars all day and eat **** from douchebag salesmen and managers. You can learn, have some down time, and learn the finer points of detailing, as well as the people skill part of the business.
Your goal at this point is to get a base/foundation of knowledge/experience under your belt, then run a small shop where you get to perfect your craft.