Here is what I contribute 70% of my business to.
1) Get about 50 pictures of the work you've done. I'm talking before and afters, in process shots, afters, glamour shots, whatever looks great.
2) Have the developed in 5x7.
3) Get a simple yet elegant photo album and place the pictures in there.
4) Wherever you go, always have the album with you.
Here's how it works.
When your making the sales pitch to somebody, you can hand them the album to look through, and narrate your services and what you can do.
such as..."We do anything from the basic wash n wax to
headlight restoration, extreme paint correction, and even mild swirl removal." Things along those lines.
When their looking through the album, tell them little pieces of info about the picture their looking at.
Such as:
"It took us 12 hours to do this car"
"I now do this BMW 525i every two weeks for the client. She was thrilled with how it turned out and wants it to keep looking that way"
"This client works at *insert name of local body shop or car dealership*" (Throwing out multiple names of local businesses makes you sound and look credible. Just be sure to be able to back it up)
Good Luck!