Select a topic to write your poem about. Then begin writing your poem. It should consist of short rhythmic stanzas that play upon the theme you have chosen. Slam poetry is typically quite strong and blunt.
Write your poetry to reflect some sort of current social more or rhetoric. Slam poetry makes a statement typically in a liberal fashion about something in modern society.
Research new slang words or relevant modern contextual references and then go back and revise your poetry, attempting to utilize these new resources. If you are trying to say the word “say,” you might try “spit” or “spew” for more impact. The more visceral the better. Do not be too formal in your presentation since formality is the antithesis to slam poetry.
Read your poem out loud to a trusted friend who will give you honest feedback—preferably someone who knows a little about slam poetry culture.
Record yourself delivering your poem. Typically slam poetry contests are entered through visual submissions or in person. Make sure you are adamant and passionate in your delivery.