It's crunch time.
Most students enter their fourth year short a recommendation or two.
Thus, it is necessary to schedule elective relating to your future residency during the summer and beginning of your forth year. Shine in these electives, because they will be your most important letters, grades, and evaluations. If you are desperate, volunteer to round on weekends, ask to see patients in clinic, etc. The key is to show interest. You should think about doing a sub-internship or an audition elective during your fourth year.