The main humorous device in "How to Become a Writer" is foreshadowed in the title. The essay is continually telling the aspiring writer to gain real-life experience, the purpose of which is to make their writing unique and insightful. However, the absurd specificity of the advice shows how similar these experiences really are for the type of people who become writers. In other words, the author uses deadpan irony to tell you how to explore your uniqueness in the same way as everyone else, with such advice as:
Early, critical disillusionment is necessary so that at 15 you can write long haiku sequences about thwarted desire. It is a pond, a cherry blossom, a wind brushing against sparrow wing leaving for mountain. Count the syllables.
This passage not only satirizes the imitativeness of young poets but also captures the strange mixture of emotional and technical advice given to writers when they are told how to process experience into a particular form.
The author frequently uses bathos as a technique to deflate the self-importance of the aspiring writer. Not only are the "unique" experiences which are so vital to the writer's development in fact formulaic and commonplace, but writers flatter themselves when they think they see and feel things differently from or more profoundly than others:
Decide that you like college life. In your dorm you meet many nice people. Some are smarter than you. And some, you notice, are dumber than you. You will continue, unfortunately, to view the world in exactly these terms for the rest of your life.
Another deflationary device can be found in the author's continual reminders that, when you show your writing to others, they will normally act with incomprehension and indifference. Instead of reassuring the aspiring writer that this only indicates their philistinism, the author suggests that this may very well be the most reasonable response.