Obviously “good” poetry is more likely to be published than bad, but poetry is a somewhat subjective thing. Not everyone agrees on what makes good poetry. Certainly the fact that you like a poem you’ve written does not make it good. Neither does that fact that your family, friends, or high school English teacher tells you that you’re a good poet. To be published, poems have to be more than “good.”
Every editor has their own idea about what constitutes good poetry, and every publication has its own style. I personally find it easier to just write my poems and then try to match them to a publication which seems a good fit, rather than trying to write poems for a specific publication. There are some basic guidelines to keep in mind as you write, though.
Free verse is much more marketable than formal poetry.
Some publications do accept formal poetry. In fact, there are several that specialize in a particular form. Free verse remains by far the most marketable, however.
Shorter poems are usually preferred.
The majority of publishers seem to prefer work between eight and twenty or thirty lines long. Some publishers want even shorter work, such as haiku. Some will accept much longer work. In general, though, shorter is more marketable. It is easier to fit in their layouts, and most have limited space. Also, long poems sometimes tend to be long-winded, losing their focus.
Publishers want poems with strong, evocative images.
They want poems that make readers feel, not poems that tell readers how to feel. Publishers want poems that paint a picture in the reader’s mind. Poetry with imagery that engages all the senses is usually preferred. Poems using concrete rather than abstract language are preferred.
Publishers also want poems that are accessible to readers; that is, poems that are easy to read and understand.
Some people think that poems are supposed to use big words and be difficult to interpret. Such poems are not very marketable, however. Simply put, readers don’t want to pay for poetry they can’t even understand. Readers need to be able to relate to poems.
Publishers want poems that are original in some way.
Editors often receive hundreds or even thousands of submissions. They look for something different. Anyone who reads much poetry is also on the lookout for something unique. Who wants to read the same old thing over and over again?
What publishers don’t want
Most do not want rhyming work. To be frank, rhyme is rarely done well in poetry.
Publishers also avoid clichés. They don’t want poems about overdone subjects like a broken heart. If you write about a subject that is commonly done in poetry, you’ll need to take a fresh approach.