The first part of any job-hunt is figuring out where you're going. On the left side of the page, write all the things you liked about the job. On the right side, list the things you disliked.
Nothing is too silly to mention.
If you disliked the army-green color of the carpet, say so. If you disliked reporting to two bosses at the same time, list that. Once finished, look for patterns. Once that's complete, write an essay about your ideal first month on the new job. Describe each day in depth.