One of the perennial and difficult to answer questions that writers get in a Q&A is "How can I get published?"
When I was in a week-long poetry workshop about 20 years ago with Tom Lux, I asked him that often-asked question. He said he always had a dozen poems "out there" at magazines and journals, and he had envelopes ready to go to other magazines so that when a poem was rejected, it went right back out again. Persistence.
It's good advice and a discipline that does not come naturally to many writers.
These days, not as many poems get mailed on paper to publishers. Online submission portals and email is often the way we submit our work.
Poet and publisher Diane Lockward has regularly posted listings of print journals that are reading submissions. She did two Summer Journals A - F and Summer Journals G - P post this year.
If you have used Submittable, a service used by a good number of organizations, it allows you to submit and track your submissions. They also offer an email newsletter that lists publishing opportunities.
I wish I knew the secret of getting a book published. I know more and more poets who are self-publishing and doing their own promotion, tours etc., but most of us want the recognition of a publisher accepting our work. Validation, perhaps.
I would also recommend using lists like one from Poets and Writers magazine to find individual publications for poems and also manuscript contests and grants. There are always some that are free, but most have a fee which is how many presses pay for publication.
The Poetry Society also offers resources of places that use poetry.
Start with the free ones, but the secret might be to always have a few poems out there as submissions.