Yeah, I look at the shop front, work out how much I would charge, write it on the back of a buisness card of mine and walk in. Introduce myself and offer the card while asking if they'd like to be one of our custies. Numbers game. Same as knocking doors really.
The custies I get from this are "tick over" income when things are bad like now. It's nearly all 7 and 14 day jobs that keep a couple of hundred a month coming in. I've got a couple of shops that are monthly, but the rest are 7/14 days.