For the clinical years, medical students are required to formulate a large portion of their schedule based purely on their interests. While this should be enjoyable, a lot of serious thought is definitely involved. Fourth-year scheduling really comes at a time when students are still unsure of what they would like to pursue as a career. One must make these important decisions based purely on what they believe they would like to do in the future, but these decisions vary dramatically with time.
I scheduled a large portion of my fourth-year around Internal Medicine because it was the most versatile of specialties. I also included some rotations that I just did not have exposure to during third-year and needed to rule out in my head.
Now, after completing the majority of fourth-year, the single most important piece of advice that I can pass on is to make fourth-year somewhat enjoyable for yourselves. This is the last time in your life that you will have minimal responsibility for many years to come. Schedule some enjoyable rotations that you are just curious about. Also, to reduce stress down the road, leave some blocks open for interviews because those are your number one priority. The heavy interview dates are between October and February.
Good luck scheduling your fourth-year rotations!