Poetry is an interesting form of writing. It is very free, has few restrictions and can be a great way to express feelings. Anyone can write poetry. Just pick up a pen and begin practicing.
Begin with an idea or inspiration. Inspiration may come at any time very unexpectedly. It may be a specific person, place or thing that evokes some sort of strong emotion. It may be more of an abstract idea or release of emotion. It may be a tiny thing at the right moment, such as a leaf tossing in the wind a certain way.
Think about form and begin to organize thoughts. Poetry comes in many forms, from epic poetry that has a story to dramatic poetry intended to be performed. Try them all out. One will come naturally. Maybe different poems fit different forms. Try free verse, which has basically no restrictions at all.
Remember rhythm and meter. There is a difference between the two, and both are equally important in poetry. Meter is the established pattern of the poem, while rhythm refers to the sound when it is spoken. Take both into consideration while writing a poem.