I did what you are planning back in the earlier 90's in Naples FL. I did not own a shop there when I arrived and eventually bought a shop I freelanced for before leaving Naples. I have also owned shops, had installers for those and freelanced myself to install residential at a competitor's shop in the same town.
Without owning my own place I did the following:
I introduce myself as a Freelance Installer of tint, had my phone number, (biz) name and card with a facing that appeared like any other card. The card was larger than the standard and had a fold. When anyone flipped the card open, they would see a mini resume of my skills and experience level.
I went around to different shops and dealerships and explained who I was, why I am there, and what my background was in brief. I would always point out the fact that every tint shop ( if that's where I was at at the time) has overflow or turn away or two they simply do not have the resources to handle at the time job. I encouraged them to call me and I'd check my schedule to see if I could be of service to them. I did this same approach for car dealerships.
If I were to supply the film, they would get a reduced cost so they had room to mark up and make a buck on the deal as well. If they supplied the film I would ask for 35-40% of customer's cost (in this scenario I'm simply a contract installer).
This is the trick, you have to do this without the appearance of building your own clients from the clients of other businesses; remaining neutral and available as freelance contract hire only.
