Okay, interesting question. First of all, I agree with the "everyone feels unprepared for residency" idea. In fact, almost everyone feels unprepared (or should at least) for becoming an attending. That's a big transition too. Regardless, I accept that you feel especially unprepared. Even students with a solid clinical education in med school can feel "especially unprepared" for some rotations (e.g. critical care) and have a lot of concerns. The amazing thing is that you, like almost all residents, will very quickly adapt. To me, the key is being truly ready to commit to residency. That means being prepared to do more than just your hospital time (80 hours isn't trivial, is it?) but also to briefly read about your patients using easily available material (e.g. UpToDate). Be honest in your first rotations about what you don't feel comfortable with (especially procedures) and accept that your first rotations will not feel great. But, the learning curve is incredible in internship and the overwhelming majority of interns quickly move to where they need to be. Perhaps aPD or others have more specific suggestions or ideas?