I'm not a good standardized test taker, but I can tell you that on my second try, I improved my scores quite significantly (not like a 50 percent to a 90) but some sections percentiles increased by as much as 25 percentage points. I am now a little above average in most sections.
Although all test takers are not alike, I found this test as well as any standardized test I have taken in my life to be deceptive. There will certainly be questions that are mind boggling, but most questions dont look too hard but are worded in such a way that it really challenges your thought processes. Like the SAT and GRE (I took both), my scores on the PCAT indicate that I am certainly not dumb, but not highly intelligent either. Some scores are average and a little above average, some scores are a little below average.
I would like to state that there is NO CORRELATION between this test and my GPA (I have completely virtually everything too with a 3.7, including both Organics). I think the difference (at least for me) is that I know what to study for classes but feel that standardized tests are much more open ended in scope of topics.
My composite score increased 15 percentile points from my first to second test. Can I keep going up? Yes and no, I know I cant ever score exceedingly well, but the test is a little more familiar to me now. Note: If this is your first attempt (the October test), you possibly have another chance to take it in January (if this date is not too late depending on your schools), but if not, there is tremendous pressure on you to do well this time. If this is your second attempt, take note of the questions on the first exam. Some will be repeat questions, and at least this time you will have a better feel in what you will be tested on. When I studied for the second time, I knew what to study and what not to study.
So in answer to your question, being familiar with the format and topics of the test (as long as you remembered them from the first test) helps tremendously.
