Small employers hiring around Denver (Denver)

Two small Denver employers told me they are hiring but have not posted yet. Any experience at all would help. They prefer people who can start within a couple of weeks. What do you write in a cold email?

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

Small employers often hire on recommendation. Ask neighbours, former co-workers and your library.