Write "darkness" in the middle of a piece of paper, then list terms related to darkness around the center. Don't try to alter your list or overthink your writing. The goal is to come up with ideas and words that conjure up images of darkness for you, which you can then employ when you sit down to compose your poetry. If you want to take your poems to the next level of creativity, try using symbolism as you write. For example, if you're thinking about how much you hate yourself for hurting others, use this as inspiration for a series of poems about self-loathing. As you write more poems, you'll notice patterns emerging that will help you decide what elements of darkness to include in future poems. Writing a dark poem may not be easy at first, but with time and practice, it gets easier. The more you write, the better you get at creating metaphors and symbols that hold great meaning for you personally. Also, remember that you don't have to follow any rules when writing a dark poem. Just write from your heart and let the magic happen!