I can tell you're looking for leads on ways to prepare during the pre-clinical years to do your best during third year. Unfortunately, the #1 thing for me has been experience. That being said, learn pathophysiology cold. Learn how to "think through" disease processes rather than just memorize diseases. Learn how to structure your differentials in a system -> process -> disease format (i.e. for syncope, think cardiac -> poor forward flow -> aortic stenosis, or vascular -> poor cerebral blood flow -> subclavian steal). The #1 most difficult thing about MS3, and what most would say differentiates a great student from an average student, is knowing what information is important, and what abnormal values are unimportant, and which ones warrant investigation or explanation (i.e. a crit of 30 often doesn't mean much, but an AlkPhos of 300+ always means something). When you're able to do that, it increases your efficiency on the wards IMMENSELY. You know what to look up and what to study, and what you can skim or skip. Your presentations become concise. You know what labs you need to know as soon as they hit the presses, etc.
And yeah, studying for the boards really helps. You learn how to connect concepts which you learned as solitary bits during MS1/MS2. Things "fit" together better.
Of course interpersonal skills, fund of knowledge, and stuff is important during third year, but most of us kinda learn that as we go. It's the whole sink or swim thing. You learn to be more assertive, more outgoing, more independent, etc because you don't have a choice.
