I'm sure this has been stated before, but this is what I did (and I found out that I passed today).
1. I took 30 seconds to quickly write down my outline for an H&P on my sheet of paper. That way I didn't forget the social history or ROS (which would be very easy to do in a stress situation-especially when some questions don't seem relevant).
2. I made sure I didn't use any "doctor words." This one was hard and took practice. Don't use any words that you would have to define if you were talking to your mom (granted that your mom isn't a doctor, nurse, etc.).
3. Spend some time with the patient on the stuff that seems irrelevant. For instance, your patient with chest pain may also have a drinking problem (or, engages in risky sexual behavior, etc.). These things are important to CS, even if "in real life" you would never waste time on safe-sex counseling when a person is likely having an MI in front of you. Take time to ask about smoking, drinking (CAGE questionnaire), and sexual practices. This stuff counts.
4. Review of systems. From what I have been told by others that have been successful on CS (and, I did this myself), you have to ask a pretty good ROS. I am not saying risk running out of time to ask a super thorough internal medicine ROS but don't discount this part. It is important. At least cover the basics: fever, chills, weight loss, GI, GU, etc.
5. Summarize, summarize, summarize. Make sure you take some time to talk to the patient about what they told you, what you found, and what you think. Ask them if there is anything else that they may feel you should know that they didn't tell you. This is another step where you shouldn't use "doctor words." Make sure you are able to explain the common problems that are found in FA for CS in a way that a lay person can understand. This is a pretty important part of CIS (from what I hear).
6. The physical exam is the least important part of the test-don't waste too much time on this step. If you take a thorough history and do a good job communicating with the patient about your findings, your thoughts, plan of action, etc. this step probably won't "make or break you." I have been told (and, from personal experience) that it is totally possible to pass without doing a thorough physical exam but that is unlikely that you will pass if you don't do a good job interviewing, have a good bedside manner, take time to summarize, etc. So, moral of the story, if you see that time is going to be an issue-get the quick and dirty part of the PE accomplished (basic heart, lungs, abdomen) but don't blow your time on a super thorough neuro exam. I found myself unable to do a very long PE for several patients and just mentioned in my summary to the patient that there were a few more things that I would like to examine in addition to the further testing that I was planning to order.
7. Smile and act pleasant. This seems obvious but after a few hours of this test the last thing you want to do is put a smile on your face and ask questions that you think are stupid. So, practice smiling (hell, smile when you pick up the phone if you have a phone case). Remember, that the patient liking you and your bedside manner matter on this test.
8. Wash your hands. Don't forget this. (Or, wear gloves)
9. The note is a pain in the butt. You will inevitably hit a character limit when typing your note (many people I talked to have this problem). So, moral of this story, look at the approved abbreviations and be able to use them without having to think about them. It is amazing how much space it will save you to use abbreviations. Also, I recommend typing the note (unless you are just incapable of doing so). In a rushed situation, all of us have the capacity to have some crappy handwriting and you would hate to fail this thing because someone couldn't read what you wrote down. Also, it may or may not help you, but I quickly put in my top differential diagnoses and plan before I typed the rest of the note. For one thing, these would be entered if I started to run out of time and for another, it helped me to keep my note going in the right direction.
I hope this helps. This part of the process is just plain stupid (I think). It is such a subjective test and quite frankly doesn't accurately evaluate how well you would do with a patient in a real situation. But, as we have all learned, medical school requires some "hoop jumping." This is just an expensive hoop.
Best of luck!