Word-of-mouth leads in Dallas

A friend who works at a local manufacturer says there are openings not advertised online. Thank you in advance. One is a print shop, one is an accounting firm and one is a clinic. 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 everything in writing and save the confirmation numbers. It saved me later.