Small employers hiring around Pittsburgh (Pittsburgh)

Two small Pittsburgh employers told me they are hiring but have not posted yet. I have read a lot of threads here and could not find my exact situation. 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 a list of who you contacted and when. It makes follow-ups easy.