Word-of-mouth leads in Minneapolis - what worked for you?

A friend who works at a local manufacturer says there are openings not advertised online. This is my first time dealing with any of this. One is a print shop, one is an accounting firm and one is a clinic. What do you write in a cold email?

Visiting in person worked for a trades job. For office jobs, email was better.

Thanks for writing this out. I went through something close to it 12 months ago, and it got easier once I kept a simple log of every call and form.