as you probably know, step 3 consists of two days:
day 1--8 blocks of 45-50 questions, which are separated by clinical environment (i.e. outpatient, inpatient, emergency room). I thought some of the questions were kind of vague, but mostly straight forward. I felt most of the questions dealt with internal medicine (>75%).
day 2--3 or 4 more MCQ type blocks of 35-40 questions followed by 9 clinical case scenarios. Make sure you familiarize yourself with the software and the types of orders you can and can not execute. Don't forget that you can order preventative type care (e.g. "advise against smoking")
I'm currently in the middle of a pretty rigorous internal medicine preliminary year. I took my step 3 at the beginning of november during an elective month. I basically studied 3-4 hours a night for 2 weeks, and went over the USMLE step 3 cd CCS twice. I read Crush Step 3 twice, focusing on peds, ob, psych and biostats (i felt pretty comfortable with medicine topics), and answered all 1000 Kaplan q bank questions. I practiced the questions in 50 question blocks so i could get used to the format.
don't sweat step 3. i passed comfortably (above average), and probably could've taken it cold and still passed (i'm not being cocky, just giving an idea of how reasonable it is).
I had no idea of how I had fared after taking the exam; just exhausted from the two days.
fyi, I got the exact same score on step 3 as i did on step 1.
good luck.