As it is nearly always the case with PR, the answer is: Play with it.
Superread the book/chapter/article and just try to dip if you feel like it. Read some sentences/paragraphs. If there's information for you - fine, perhaps read another few sentences/paragraphs.
If nothing is there, go up again to Superreading.
Remain curious and playful and with experience you develop a sense for your hunches.
Have fun!
Jens
