Brainstorm a topic for your poem. Ideally this is something that you are familiar with or have a fairly broad knowledge base about. Incorporate topics that frustrate you or cause you to laugh during the course of an average day. Topics that you know about are easier to write on than things you do not have much knowledge of.
Outline the length and scansion of your poem. Write the poem either in an established structure or free-form. Established poem makeup like a haiku has a concrete form in it's three lines of five syllables in the first, seven syllables in the second and five syllables in the last line. A limerick usually has seven, seven, five, five and seven syllables in its five lines. However, writing the poem in free-form verse is also an option that does not require any structure of lines, syllables or rhymes. Free-form poetry does not require rhymes for a poem, but they often make a poem more catchy and lyrical.
Write down ideas for lines or couplets that rhyme or lines that portray the hilarity of your subject. This will help you brainstorm content to include in your poem.
Piece the lines together to form the poem. The beginning of the poem should hook the reader to want to continue reading the rest of the poem. The ending line should leave the reader thinking about the poem. Ideally, the final line should be the most humorous line of the poem so that it causes the reader to think about what was said and dwell on why it was funny.