In addition to the rest of the advice, I would add, that you must, you ABSOLUTELY must keep in mind your purpose. This is much more applicable to nonfiction, but it still applies.
How much of the book do you have to know? How much do you want to know? (j/k 
)
I have found that once I got over the conscious having to read every word, activation is much easier. Relax, you subconscious knows it, and simply find what you need.
When you PR a few books a day, you kinda have to learn to let go, and get over the conscious having to know everything.
