Don't freak about the ITE your CA1 year. Similarly, I wouldn't recommend doing questions at this point in your training. Read Baby Miller and/or Morgan and Mikhail. Know them cold. Have Barash or Miller as a reference for when you start getting more complicated cases, vascular, thoracic, neuro. Buy a good cardiac book for that rotation which will probably be CA2. I really like the NYSORA book for regional, most of it is online though.
When the time comes to focus on questions, there are several choices right now. Realize that your exam next year will (or should) be on computer, but the format will be basically the same. Here's the some of the current choices:
1) Hall: Many people use it. Tough questions and great explanations. Probably worth using.
2) Dershewitz: Again, many people have this book. I'm not a huge fan, but the questions and explanations are good. I find the stems fairly short compared to the real thing though. If anything, the exam will be longer questions like Step 3 has went to.
3) Chu: A real sleeper. 2 released exams from 1993. I'll admit some questions are very very old with topics and drugs no longer tested, but most of the topics are repeated from year to year. The explanations are outstanding.
4) You can get old exams with answers from the ASA website under the continuing ed section. Unfortunately, 1995 is the latest one available and only the answers, not explanations are presented.
5) Etherprep online. Do a search, some people are using it. May become the new standard as questions can be added easily without publishing new editions. And we're used to things like the Kaplan online test prep.
6) Medtext questions. Remembered questions. I have seen several books of them. Quality seems to vary a bit as some questions are remembered better than others.