So...I used to give people the standard advice about reading more widely (periodicals, books, etc.), but I eventually rethought it. The basic issue is this: yes, CARS (generally speaking) favors active readers (and the science sections are similarly much easier for people who have spent a lot of time reading research articles), but the problem is that most people prepare for the MCAT in a pretty short, focused time frame, often with competing life obligations—and randomly reading outside material isn't a very time-effective or efficient way of improving in CARS specifically.
In other words, if you could snap your fingers and retroactively make yourself a philosophy/history/English double major, yeah, that would probably correlate to an easier time on the CARS section of the MCAT. But you've got to work with where you're at now, and you've got to work towards the specific goal of doing well on CARS.
So, as others have said, practice practice practice (using representative materials) and work to understand those materials inside and out. A broad range of third-party materials (exams, passages, etc.) can be helpful for pacing/timing/techniques. Most MCAT courses deal with CARS at least to some extent, and that could be useful too if that's an available option for you. In other words, work to get better at CARS in a specific way.
The final thing I'd note is that CARS isn't just a generic reading comprehension section - it has its own specific structure, logic, and feel. Google "AAMC what's on the MCAT" and you'll find a landing site on the AAMC's page where they provide a lot of information about how they build the exam, including PDFs describing the science and CARS section in a fair amount of detail. It's kind of dry reading, but it's also empowering to read what the test makers themselves directly say about it.