How many practice tests have you taken at this point? My personal opinion on this, is B/Bs the part of the test that is most heavy on graphical analysis. So its the part that benefits most from practice exams. (I'm taking it 05/23. Went from ~50% --> 81% averages after taking 7 practice exams + Uworld fill ins.)
As the comment above said, a little more info would help. When you review your exams do you reason out why you missed the question? If so, can you tell us?
Such as... Do you feel rock solid on your content? Have you struggled applying what you've read to visual interpretations? Maybe you feel strapped for time and as a result you're not extracting everything you need from the passage. So you miss stuff right in front of you. Referencing your non-science background, perhaps you're just not used to these types of questions, and could really benefit from practice under timed pressure.
IMO
C/P - Straight practice problems.
CARS - How's your reading comprehension?
B/B - How's your graphical/ scientific study comprehension?
P/S - Have you memorized all the terms and can apply them?