Word-of-mouth leads in Phoenix - any advice?

A friend who works at a local manufacturer says there are openings not advertised online. I have been trying to stay organised about it. They prefer people who can start within a couple of weeks.

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

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