Jobsite signs don't work in every community. For example in my community, jobsite signs are prohibited. And, if you put one up, the building department removes it and sends you a bill for $45 disposal fee.
I'm in with Paintsmith. Give your prospect a good face to face sales call. Nothing works better than asking for their business on the spot!
Example: A person approaches me as I am leaving my van for lunch. "I was thinking of doing some painting". My first question out of the box is: "Are you seeking a professional or would you like some professional consultation? I do both for a fee. Let's set an appointment." Don't "ask" for an appointment, command an appointment with "let's set an appointment" Try it..see what happens.
It may seem too demanding, but if a professional like you doesn't take control of the situation, some schmuck is going to booger up that job.
Have passion for their needs and be proud of your work.
Michael