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

A friend who works at a local manufacturer says there are openings not advertised online. There are 9 people counting on me, so I am trying to be careful. They prefer people who can start within a couple of weeks. Should I visit in person?

A short email with two sentences about what you can do and your résumé attached worked for me. I followed up after a week.

Keep a list of who you contacted and when. It makes follow-ups easy.