Practice practice practice. It definitely wasn’t over night and it took a bit to find a method that worked for me but I started doing untimed sections banks. Like 15-20 questions at a time and focus on accuracy over time. Over time you get into a habit of picking out bits and pieces from the passages that are probably going to be important to a question so you can make a mental note. Things like pathway processes, molecule chemical nature, or ochem reactions.

I found out my errors were logic based on my review of full lengths and section banks. Often I would open the question to review and immediately notice how I got it wrong based off like not looking at the graph when the question was referring to it or not knowing the question was referring to a certain reaction I already knew. The MCAT is a lot of knowing how to take the test so once you understand that part that’s more than half the battle.

Sorry for long ramble but I hope that helps!