Concerning science courses, no matter what class it is (bio,chem,physics,math), I have the following philosophy:
1. Identify high yield material (i.e. stuff that will be on the exam) as opposed to low yield (things that the professor considers not too important for the course)
2. Find the sections in your textbook that teaches these high yield items and do every single practice problems you can find in the textbook and past exams.
3. Finally, review these same exact problems you just did the day before/morning of an exam - this will give you the confidence needed to avoid test anxiety and will also remind you of any weird "tricks" associated with a certain problem.
The philosophy has been 100% foolproof for me personally - and again, it's great because it applies to ALL science prereqs. Before I knew of this method, I got D+ in singlevar calc, B in multivar calc, B in pchem I. After I figured it out, everything was all A/A-. Physics A+,A,A- // Chem A-,A,A-,A- // Bio A,A,A,A // Stats A. Science gpa went from 2.15 to 3.61 from freshmen fall quarter to sophomore spring quarter. I know it seems braggy, but since this is an anonymous forum I wanted to share this because it works for me very well. Good luck!