Reread and reread until it feels right. Most forms of poetry are based on rhythm. There are a few modern forms where it is more important to make a shape on the page, but most of what people accept as poetry is based on how it sounds and feels. When you are looking over a poem you have written, read it out loud. Do you stumble trying to read it? Does it flow well? Can you have someone else read it? Do they stumble? Do they read it like you wrote it? Does the poem feel right? Look for the stumbles and the jerks and fits within the reading, and try to improve those.