I thought the highlighting tool was very useful back when I took the exam! When I was going through the RC sections, I would first read through the section pretty quickly and highlight any facts or points that seemed to be of importance or general value. Many of those highlighted portions would then show up in answer choices, so it made going back into the passage to look for what I thought was important so much easier!
It honestly might be worth practicing using a similar tool now. Try downloading science articles online and highlighting them with PDF viewers as you read through. Over time, you will probably become much more efficient and be better able to point out important facts!