Choose two things that are opposites. It could be the opposite sides of a question. Humor is good. The poem should be two or four lines long. The first two and the last two lines should rhyme.
Sight rhymes are acceptable.
What a lot of people do on a hard test. Maybe it is as beautiful as a white dove, Because love is so fine, This is something that I know is mine. Because a great smile brightens up the day, This has made my day better in every way. It could be purple, or even blue. Because truth is better than a lie, I want the truth even from my special guy.