in regards to the plant bio stuff, this is one aspect of the biology section that most people tend to overlook and i took the PCAT in october and there was 2-4 questions on this. Also the cellular stuff is pretty basic (high school basic) however i would make sure you know the physiology/anatomy stuff in and out especially hormones (where it is secreted from, function and where it acts and whether it has agonist or antagonist effect with other hormones) also renal function was another big part.
The chemistry/Math section was one of those sections that everyone can do but what makes the difference is how fast you can finish this in. These are those sections that are notorious among for PCAT test takers for rushing or not having enough time to finish. So time yourself on this one and remember no calculators or periodic table!
For verbal section I would read scientific american and look up words you dont know and know the word prefixes and suffixes and english words with greek or latin roots. In addition use practice tests to test yourself and know the common words they usually ask. I did pretty well on this section with this approach.
The writing section: The best way to prepare for this section is do some research on common health or political issues like rise in obesity rates among teens (why it has developed and what are ways you can help to lower rates).
Also on the day before of the PCAT make sure you dont stress yourself and get plenty of sleep and dont over-caffeinated your brain. if you have any specific question PM me or reply to this post. Good Luck !!😍