Make sure you have the necessary contact information and learn the specific guidelines for each journal where you are submitting work. Contact information and guidelines can often be found on the journal's website under "Submissions" or "Guidelines for Submitting your Work." Guideline information includes how many poems the editors are willing to look at. According to Charlie Hughes, writer and owner of Wind Publications, "Magazines generally prefer no more than three to five poems in one submission. Most editors like to see more than one poem with each submission so that they may better judge the writer's ability." (See reference 1.)
Make sure there is an aesthetic fit. If you blindly send your poetry to a journal without taking the time to read what they publish, either online or in hard copy, you could be wasting your time. It's essential to read the journal first. If they don't publish work that you like or that doesn't look like what you write, you may want to move on.
Confirm that the journal is accepting submissions. Check to see if if the journal has an "Open Reading Period." That is, is the journal currently accepting unsolicited submissions? Oftentimes this can be found relatively easy on a journal's home page. If it's not prominently displayed, look under the submissions guidelines or call to inquire.
Create a cover letter. Some journals will only look at work accompanied by some sort of introduction from the author. The cover letter should be brief---never more than a page. Make sure all your contact information is listed and simply introduce who you are and the titles of the poems you are sending to the journal. You might also include a short bio that lists any previous publication of your poetry.