Understand your theme: A theme is not the same as a topic.
For example, a topic about life might be “friendship” but a theme would be something like “how friendship enriches life.”
Know your purpose before you start writing: How do you want people to feel after reading your poem?
Do you want them to be happy, sad, surprised, shocked, peaceful, angry?
Avoid common subjects: It can seem like everything has been written about before, but really try to choose your own topic. Writing about your own experience can help you to do this.
Try telling a story about your life.
A poem doesn’t have to rhyme: Most poems don’t rhyme. They use words creatively to express meaning but most poems don’t rhyme.
Use metaphors: You can learn about metaphors and how to use them at this link.
Use imagery: You can learn about imagery and how to use it at this link.