3rd year is different because you're studying for two different types of evaluation. the first is subjective evals by attendings and residents. some of it is personality, which you can't (really) control, but they use pimp questions to evaluate you as well. Most of their questioning centers around your patients and the conditions they have. For this you need to know your patients well and have read at least something basic about their diagnosis (like in CMDT, e-medicine.com or something similar). Attendings are known to be tangential in this type of setting though so it's basically impossible to prepare for every question they'll ask. However, in a way this is the most important part of studying since not knowing the basics during rounds can make you lose a lot of confidence. (At least this happens to me.) So I usually try to read something about the diagnoses my team is working on at any given moment. If I'm super tired or don't feel like working I read something brief like the emedicine entries. If I want to put more effort in I will read Harrison's or look up a review article. I usually don't bring my studying home with me because it's hard for me to get motivated to read once I get home from the hospital, so i try to read during lunch or other downtime during the day.
The good news is that if you read about your patients you will learn a lot about their conditions, at least in Medicine-ish fields (i.e. Medicine, Peds, Neuro) and this will help prepare for the other evaluation -- end of rotation exams. I did not find this to be as true in Surgery or Ob-Gyn. For example if you rotate in an adult medicine unit you WILL see patients with pneumonia, diabetes, hypertension, heart failure, PE, etc. If you rotate on Peds outpatient, you WILL see asthma, ear infections, ADD... Common things are common, and they're also what make up the bulk of the shelf exams. So if you read about your patients, you are also studying for exams. For me at least, it's easier to concentrate on reading if there's a real clinical case to think about in connection with it.
Anyway these are just some thoughts I had about what 3rd year studying has been like. I found it much more tolerable than studying during preclinical years, when I just felt like I was cramming random facts into my brain.