canadian moving to LA where do I start?

I doubt you could legally get into the US if you plan on working in retail, you couldn't get the labour certification for that. The only way would be family re-unification, which means you must have a close relative who is a US citizen (or in some cases, a permanent resident).

Why were you planning to move to LA? You have friends, or relatives there? Or just because its there?

More information may help us help you better.

Well, unless you are somehow qualified for a work visa of some sort and you're offered a job with a design company in LA, hiring a lawyer isn't going to do you any good.

Honestly, my advice would be to try and find a job with a design company in Toronto, establish yourself as totally awesome in the industry, and then in a few years start looking for a job in LA after you're known. IF there is a company in Toronto that has offices in LA, get a job with them. Then you could transfer.

Or go back to school and get a university degree that would qualify for a TN.

You could always go in as a student, F-1. F-1 students are allowed to work for up to 20 hours a week during the course of study (provided it's relevant to the course of study) and also there is optional practical training, which gives you a work permit for a year at the end of the course of study.

It's a pretty common thing for people starting out in the fashion industry to do it that way.

Has to be a significant course of study though, like an associate's degree.